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36 vulnerabilities by thephpleague
CVE-2024-58382 (GCVE-0-2024-58382)
Vulnerability from nvd – Published: 2026-09-09 13:31 – Updated: 2026-09-09 14:54
VLAI
EPSS
VEX
Title
league/commonmark before 2.6.0 Denial of Service via Quadratic Complexity
Summary
league/commonmark versions before 2.6.0 contain polynomial time complexity vulnerabilities in Markdown parsing that allow attackers to cause denial of service. Attackers can submit carefully crafted Markdown inputs designed to trigger worst-case performance, and sending multiple requests in parallel exhausts CPU resources and PHP-FPM processes.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 14:53 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/league-commo… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
0 , < 2.6.0
(semver)
Unaffected: 2.6.0 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2024-12-07 00:00
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CVE-2026-86435 (GCVE-0-2026-86435)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-09 14:32
VLAI
EPSS
VEX
Title
commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote
Summary
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 14:31 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-1… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86434 (GCVE-0-2026-86434)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-19 14:21
VLAI
EPSS
VEX
Title
commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision
Summary
league/commonmark versions >= 2.0.0 and < 2.8.4 (patched in 2.9.0) contain a denial of service vulnerability in UniqueSlugNormalizer::normalize(), which restarts its numeric-suffix search from 1 on every slug collision, resulting in O(K^2) time complexity for K headings that collapse to the same base slug. The vulnerable path is reached when HeadingPermalinkExtension, FootnoteExtension, or TableOfContentsExtension is registered. An unauthenticated attacker can force many headings onto a single base slug (e.g., via empty ATX headings, identical heading text, or punctuation-only headings) in a small Markdown document, consuming excessive CPU and denying service.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 17:42 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-2… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
2.0.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86433 (GCVE-0-2026-86433)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-08 12:50
VLAI
EPSS
VEX
Title
commonmark 1.5.0 before 2.8.4 Denial of Service via Attributes
Summary
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 12:50 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-1… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86432 (GCVE-0-2026-86432)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-10 15:04
VLAI
EPSS
VEX
Title
commonmark 2.0.0 before 2.8.4 Denial of Service via XML
Summary
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Severity
5.3 (Medium)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-10 14:22 UTC
CWE
- CWE-405 - Asymmetric Resource Consumption (Amplification)
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-2… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
2.0.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86431 (GCVE-0-2026-86431)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-08 13:33
VLAI
EPSS
VEX
Title
commonmark before 2.9.1 XSS via AttributesExtension form feed bypass
Summary
league/commonmark (thephpleague/commonmark) versions >= 2.7.0 and < 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte (e.g. {\x0Conclick="alert(1)"}) bypasses the AttributesHelper::filterAttributes() 'on*' event-handler filter because PHP's trim() does not strip U+000C, causing the attribute to be written verbatim into the output where browsers parse it as a genuine event handler. The same prefix also defeats the allow_unsafe_links check, allowing javascript: URIs through href/src attributes even when allow_unsafe_links is false. Exploitation requires processing untrusted Markdown with the AttributesExtension enabled; the injected script executes when the rendered HTML is viewed. Fixed in 2.9.1.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 13:30 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://github.com/thephpleague/commonmark/commit… | patch |
| https://www.vulncheck.com/advisories/commonmark-b… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
2.7.0 , < 2.9.1
(semver)
Unaffected: 2.9.1 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-09 00:00
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CVE-2026-86430 (GCVE-0-2026-86430)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-09 14:31
VLAI
EPSS
VEX
Title
league/commonmark before 2.9.1 Denial of Service via parsing
Summary
league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detection, reference link label lookup, and emphasis delimiter processing that perform super-linear work on crafted input. Attackers can submit specially crafted Markdown with long backtick runs, nested brackets, or delimiter sequences to consume disproportionate CPU time and prevent legitimate requests from completing.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 14:31 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/league-commo… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
0.6.0 , < 2.9.1
(semver)
Unaffected: 2.9.1 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-09 00:00
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CVE-2026-86429 (GCVE-0-2026-86429)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-19 14:21
VLAI
EPSS
VEX
Title
commonmark before 2.9.1 Denial of Service via SmartPunct and Attributes
Summary
The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 17:41 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-b… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.9.1
(semver)
Unaffected: 2.9.1 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-09 00:00
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CVE-2026-86428 (GCVE-0-2026-86428)
Vulnerability from nvd – Published: 2026-09-07 12:53 – Updated: 2026-09-08 12:50
VLAI
EPSS
VEX
Title
commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes
Summary
commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 12:50 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-1… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.10.0
(semver)
Unaffected: 2.10.0 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-11 00:00
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CVE-2026-71488 (GCVE-0-2026-71488)
Vulnerability from nvd – Published: 2026-08-06 20:37 – Updated: 2026-08-07 17:17
VLAI
EPSS
VEX
Title
league/commonmark: Quadratic-time denial of service when parsing crafted Markdown
Summary
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translate between character positions and byte positions, and the Autolink extension can also copy and validate the remaining line at every URL-like prefix, allowing an attacker who can submit Markdown for conversion to consume disproportionate CPU time with a comparatively small request. This issue is fixed in 2.9.0.
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-07 17:16 UTC
CWE
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
>= 0.6.0, < 2.9.0
|
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CVE-2026-71478 (GCVE-0-2026-71478)
Vulnerability from nvd – Published: 2026-08-06 20:30 – Updated: 2026-08-07 17:05
VLAI
EPSS
VEX
Title
league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes
Summary
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.
Severity
6.1 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-07 17:04 UTC
CWE
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
>= 1.5.0, <= 2.8.3
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CVE-2026-33347 (GCVE-0-2026-33347)
Vulnerability from nvd – Published: 2026-03-24 19:26 – Updated: 2026-03-26 19:52
VLAI
EPSS
VEX
Title
league/commonmark has an embed extension allowed_domains bypass
Summary
league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like youtube.com.evil passes the allowlist check when youtube.com is an allowed domain. This issue has been patched in version 2.8.2.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-26 19:34 UTC
CWE
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
>= 2.3.0, < 2.8.2
|
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CVE-2026-30838 (GCVE-0-2026-30838)
Vulnerability from nvd – Published: 2026-03-07 16:00 – Updated: 2026-03-09 18:26
VLAI
EPSS
VEX
Title
league/commonmark: DisallowedRawHtml extension bypass via whitespace in HTML tag names
Summary
league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing >. For example, <script\n> would pass through unfiltered and be rendered as a valid HTML tag by browsers. This is a cross-site scripting (XSS) vector for any application that relies on this extension to sanitize untrusted user input. All applications using the DisallowedRawHtml extension to process untrusted markdown are affected. Applications that use a dedicated HTML sanitizer (such as HTML Purifier) on the rendered output are not affected. This issue has been patched in version 2.8.1.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-09 17:38 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
< 2.8.1
|
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CVE-2025-46734 (GCVE-0-2025-46734)
Vulnerability from nvd – Published: 2025-05-05 19:52 – Updated: 2025-05-06 13:47
VLAI
EPSS
VEX
Title
league/commonmark Cross-site Scripting vulnerability in Attributes extension
Summary
league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.
Severity
6.4 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-05-06 13:46 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
< 2.7.0
|
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CVE-2023-37260 (GCVE-0-2023-37260)
Vulnerability from nvd – Published: 2023-07-06 15:09 – Updated: 2024-11-06 16:50
VLAI
EPSS
VEX
Title
league/oauth2-server key exposed in exception message when passing as string and providing invalid pass phrase
Summary
league/oauth2-server is an implementation of an OAuth 2.0 authorization server written in PHP. Starting in version 8.3.2 and prior to version 8.5.3, servers that passed their keys to the CryptKey constructor as as string instead of a file path will have had that key included in a LogicException message if they did not provide a valid pass phrase for the key where required. This issue has been patched so that the provided key is no longer exposed in the exception message in the scenario outlined above. Users should upgrade to version 8.5.3 to receive the patch. As a workaround, pass the key as a file instead of a string.
Severity
8.2 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-11-06 16:48 UTC
CWE
- CWE-209 - Generation of Error Message Containing Sensitive Information
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/oauth2-server/sec… | x_refsource_CONFIRM |
| https://github.com/thephpleague/oauth2-server/pull/1353 | x_refsource_MISC |
| https://github.com/thephpleague/oauth2-server/rel… | x_refsource_MISC |
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | oauth2-server |
Affected:
>= 8.3.2, < 8.5.3
|
|
| oauth2-server_project | oauth2-server |
Affected:
8.3.2 , < 8.5.3
(custom)
cpe:2.3:a:oauth2-server_project:oauth2-server:*:*:*:*:*:*:*:* |
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CVE-2024-58382 (GCVE-0-2024-58382)
Vulnerability from cvelistv5 – Published: 2026-09-09 13:31 – Updated: 2026-09-09 14:54
VLAI
EPSS
VEX
Title
league/commonmark before 2.6.0 Denial of Service via Quadratic Complexity
Summary
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Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 14:53 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/league-commo… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
0 , < 2.6.0
(semver)
Unaffected: 2.6.0 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2024-12-07 00:00
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CVE-2026-86435 (GCVE-0-2026-86435)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-09 14:32
VLAI
EPSS
VEX
Title
commonmark 1.5.0 before 2.8.4 Denial of Service via Footnote
Summary
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Footnote extension that fails to deduplicate footnote definitions. Attackers can craft documents with duplicate footnote definitions and references to create quadratic output expansion, consuming excessive memory and CPU to exhaust server resources.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 14:31 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-1… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.8.4
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Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86434 (GCVE-0-2026-86434)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-19 14:21
VLAI
EPSS
VEX
Title
commonmark 2.0.0 through 2.8.3 Denial of Service via Slug Collision
Summary
league/commonmark versions >= 2.0.0 and < 2.8.4 (patched in 2.9.0) contain a denial of service vulnerability in UniqueSlugNormalizer::normalize(), which restarts its numeric-suffix search from 1 on every slug collision, resulting in O(K^2) time complexity for K headings that collapse to the same base slug. The vulnerable path is reached when HeadingPermalinkExtension, FootnoteExtension, or TableOfContentsExtension is registered. An unauthenticated attacker can force many headings onto a single base slug (e.g., via empty ATX headings, identical heading text, or punctuation-only headings) in a small Markdown document, consuming excessive CPU and denying service.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 17:42 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-2… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
2.0.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86433 (GCVE-0-2026-86433)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-08 12:50
VLAI
EPSS
VEX
Title
commonmark 1.5.0 before 2.8.4 Denial of Service via Attributes
Summary
commonmark versions from 1.5.0 before 2.8.4 contain a denial of service vulnerability in the Attributes extension where AttributesListener::findTargetAndDirection() performs quadratic-time sibling list scanning. Unauthenticated attackers can submit approximately 32 KB of repeated attribute blocks to cause parsing to take over 5 seconds, exhausting server resources.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 12:50 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-1… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86432 (GCVE-0-2026-86432)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-10 15:04
VLAI
EPSS
VEX
Title
commonmark 2.0.0 before 2.8.4 Denial of Service via XML
Summary
commonmark versions from 2.0.0 before 2.8.4 contain a denial of service vulnerability in XmlRenderer that emits depth-proportional indentation for every XML tag. Attackers can provide deeply nested Markdown or AST structures to cause quadratic memory consumption and output amplification, exhausting server resources.
Severity
5.3 (Medium)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-10 14:22 UTC
CWE
- CWE-405 - Asymmetric Resource Consumption (Amplification)
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-2… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
2.0.0 , < 2.8.4
(semver)
Unaffected: 2.8.4 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-03 00:00
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CVE-2026-86431 (GCVE-0-2026-86431)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-08 13:33
VLAI
EPSS
VEX
Title
commonmark before 2.9.1 XSS via AttributesExtension form feed bypass
Summary
league/commonmark (thephpleague/commonmark) versions >= 2.7.0 and < 2.9.1 contain a cross-site scripting vulnerability in the AttributesExtension. Prefixing an attribute name with a single U+000C form feed byte (e.g. {\x0Conclick="alert(1)"}) bypasses the AttributesHelper::filterAttributes() 'on*' event-handler filter because PHP's trim() does not strip U+000C, causing the attribute to be written verbatim into the output where browsers parse it as a genuine event handler. The same prefix also defeats the allow_unsafe_links check, allowing javascript: URIs through href/src attributes even when allow_unsafe_links is false. Exploitation requires processing untrusted Markdown with the AttributesExtension enabled; the injected script executes when the rendered HTML is viewed. Fixed in 2.9.1.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 13:30 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://github.com/thephpleague/commonmark/commit… | patch |
| https://www.vulncheck.com/advisories/commonmark-b… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
2.7.0 , < 2.9.1
(semver)
Unaffected: 2.9.1 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-09 00:00
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CVE-2026-86430 (GCVE-0-2026-86430)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-09 14:31
VLAI
EPSS
VEX
Title
league/commonmark before 2.9.1 Denial of Service via parsing
Summary
league/commonmark versions before 2.9.1 contain multiple denial of service vulnerabilities in fenced code block detection, reference link label lookup, and emphasis delimiter processing that perform super-linear work on crafted input. Attackers can submit specially crafted Markdown with long backtick runs, nested brackets, or delimiter sequences to consume disproportionate CPU time and prevent legitimate requests from completing.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-09 14:31 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/league-commo… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
0.6.0 , < 2.9.1
(semver)
Unaffected: 2.9.1 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-09 00:00
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CVE-2026-86429 (GCVE-0-2026-86429)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-19 14:21
VLAI
EPSS
VEX
Title
commonmark before 2.9.1 Denial of Service via SmartPunct and Attributes
Summary
The league/commonmark (thephpleague/commonmark) library in versions >= 1.5.0 and < 2.9.1 contains quadratic parsing complexity in its SmartPunctExtension and AttributesExtension. When either extension is explicitly registered on the Environment (they are not enabled by default and are excluded from the standard CommonMark and GitHub-Flavored Markdown converters), an unauthenticated attacker can submit small, specially crafted Markdown documents — such as text alternating with unpaired quotes, contiguous runs of block-level attribute blocks, or repeated class attributes — to trigger disproportionate CPU consumption and cause a denial of service. Fixed in 2.9.1.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-18 17:41 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-b… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.9.1
(semver)
Unaffected: 2.9.1 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-09 00:00
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CVE-2026-86428 (GCVE-0-2026-86428)
Vulnerability from cvelistv5 – Published: 2026-09-07 12:53 – Updated: 2026-09-08 12:50
VLAI
EPSS
VEX
Title
commonmark 1.5.0 before 2.10.0 Denial of Service via Attributes
Summary
commonmark versions from 1.5.0 before 2.10.0 contain a denial of service vulnerability in the AttributesExtension when processing distinctly-named attributes. Attackers can submit Markdown with numerous distinct attribute names to cause quadratic-time attribute merging and filtering, consuming disproportionate CPU resources and preventing legitimate requests from completing.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-08 12:50 UTC
CWE
- CWE-407 - Inefficient Algorithmic Complexity
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | vendor-advisory |
| https://www.vulncheck.com/advisories/commonmark-1… | third-party-advisory |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
1.5.0 , < 2.10.0
(semver)
Unaffected: 2.10.0 (semver) cpe:2.3:a:thephpleague:commonmark:*:*:*:*:*:*:*:* |
Date Public
2026-08-11 00:00
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CVE-2026-71488 (GCVE-0-2026-71488)
Vulnerability from cvelistv5 – Published: 2026-08-06 20:37 – Updated: 2026-08-07 17:17
VLAI
EPSS
VEX
Title
league/commonmark: Quadratic-time denial of service when parsing crafted Markdown
Summary
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 0.6.0 until 2.9.0, specially crafted Markdown lines can cause the parser to have quadratic time complexity when converting, because several parsing paths repeatedly rescan growing portions of a line to translate between character positions and byte positions, and the Autolink extension can also copy and validate the remaining line at every URL-like prefix, allowing an attacker who can submit Markdown for conversion to consume disproportionate CPU time with a comparatively small request. This issue is fixed in 2.9.0.
Severity
7.5 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-07 17:16 UTC
CWE
Assigner
References
5 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
>= 0.6.0, < 2.9.0
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CVE-2026-71478 (GCVE-0-2026-71478)
Vulnerability from cvelistv5 – Published: 2026-08-06 20:30 – Updated: 2026-08-07 17:05
VLAI
EPSS
VEX
Title
league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes
Summary
league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.
Severity
6.1 (Medium)
SSVC
Exploitation: poc
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-08-07 17:04 UTC
CWE
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
>= 1.5.0, <= 2.8.3
|
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CVE-2026-33347 (GCVE-0-2026-33347)
Vulnerability from cvelistv5 – Published: 2026-03-24 19:26 – Updated: 2026-03-26 19:52
VLAI
EPSS
VEX
Title
league/commonmark has an embed extension allowed_domains bypass
Summary
league/commonmark is a PHP Markdown parser. From version 2.3.0 to before version 2.8.2, the DomainFilteringAdapter in the Embed extension is vulnerable to an allowlist bypass due to a missing hostname boundary assertion in the domain-matching regex. An attacker-controlled domain like youtube.com.evil passes the allowlist check when youtube.com is an allowed domain. This issue has been patched in version 2.8.2.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-26 19:34 UTC
CWE
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
| https://github.com/thephpleague/commonmark/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
>= 2.3.0, < 2.8.2
|
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CVE-2026-30838 (GCVE-0-2026-30838)
Vulnerability from cvelistv5 – Published: 2026-03-07 16:00 – Updated: 2026-03-09 18:26
VLAI
EPSS
VEX
Title
league/commonmark: DisallowedRawHtml extension bypass via whitespace in HTML tag names
Summary
league/commonmark is a PHP Markdown parser. Prior to version 2.8.1, the DisallowedRawHtml extension can be bypassed by inserting a newline, tab, or other ASCII whitespace character between a disallowed HTML tag name and the closing >. For example, <script\n> would pass through unfiltered and be rendered as a valid HTML tag by browsers. This is a cross-site scripting (XSS) vector for any application that relies on this extension to sanitize untrusted user input. All applications using the DisallowedRawHtml extension to process untrusted markdown are affected. Applications that use a dedicated HTML sanitizer (such as HTML Purifier) on the rendered output are not affected. This issue has been patched in version 2.8.1.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-03-09 17:38 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
1 reference
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
< 2.8.1
|
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CVE-2025-46734 (GCVE-0-2025-46734)
Vulnerability from cvelistv5 – Published: 2025-05-05 19:52 – Updated: 2025-05-06 13:47
VLAI
EPSS
VEX
Title
league/commonmark Cross-site Scripting vulnerability in Attributes extension
Summary
league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.
Severity
6.4 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-05-06 13:46 UTC
CWE
- CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/commonmark/securi… | x_refsource_CONFIRM |
| https://github.com/thephpleague/commonmark/commit… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | commonmark |
Affected:
< 2.7.0
|
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CVE-2023-37260 (GCVE-0-2023-37260)
Vulnerability from cvelistv5 – Published: 2023-07-06 15:09 – Updated: 2024-11-06 16:50
VLAI
EPSS
VEX
Title
league/oauth2-server key exposed in exception message when passing as string and providing invalid pass phrase
Summary
league/oauth2-server is an implementation of an OAuth 2.0 authorization server written in PHP. Starting in version 8.3.2 and prior to version 8.5.3, servers that passed their keys to the CryptKey constructor as as string instead of a file path will have had that key included in a LogicException message if they did not provide a valid pass phrase for the key where required. This issue has been patched so that the provided key is no longer exposed in the exception message in the scenario outlined above. Users should upgrade to version 8.5.3 to receive the patch. As a workaround, pass the key as a file instead of a string.
Severity
8.2 (High)
SSVC
Exploitation: none
Automatable: yes
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-11-06 16:48 UTC
CWE
- CWE-209 - Generation of Error Message Containing Sensitive Information
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://github.com/thephpleague/oauth2-server/sec… | x_refsource_CONFIRM |
| https://github.com/thephpleague/oauth2-server/pull/1353 | x_refsource_MISC |
| https://github.com/thephpleague/oauth2-server/rel… | x_refsource_MISC |
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| thephpleague | oauth2-server |
Affected:
>= 8.3.2, < 8.5.3
|
|
| oauth2-server_project | oauth2-server |
Affected:
8.3.2 , < 8.5.3
(custom)
cpe:2.3:a:oauth2-server_project:oauth2-server:*:*:*:*:*:*:*:* |
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