CWE-94
Allowed-with-ReviewImproper Control of Generation of Code ('Code Injection')
Abstraction: Base · Status: Draft
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
9576 vulnerabilities reference this CWE, most recent first.
GHSA-9G2H-FH68-3P2V
Vulnerability from github – Published: 2025-12-15 21:30 – Updated: 2025-12-24 18:30Zomplog 3.9 contains a remote code execution vulnerability that allows authenticated attackers to inject and execute arbitrary PHP code through file manipulation endpoints. Attackers can upload malicious JavaScript files, rename them to PHP, and execute system commands by exploiting the saveE and rename actions in the application.
{
"affected": [],
"aliases": [
"CVE-2023-53888"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-15T21:15:51Z",
"severity": "HIGH"
},
"details": "Zomplog 3.9 contains a remote code execution vulnerability that allows authenticated attackers to inject and execute arbitrary PHP code through file manipulation endpoints. Attackers can upload malicious JavaScript files, rename them to PHP, and execute system commands by exploiting the saveE and rename actions in the application.",
"id": "GHSA-9g2h-fh68-3p2v",
"modified": "2025-12-24T18:30:17Z",
"published": "2025-12-15T21:30:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2023-53888"
},
{
"type": "WEB",
"url": "https://web.archive.org/web/20080616153330/http://zomp.nl/zomplog"
},
{
"type": "WEB",
"url": "https://www.exploit-db.com/exploits/51624"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/zomplog-remote-code-execution-via-authenticated-file-manipulation"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
]
}
GHSA-9G2Q-259C-66MQ
Vulnerability from github – Published: 2024-11-26 15:31 – Updated: 2025-11-04 00:32Memory safety bugs present in Firefox 132, Firefox ESR 128.4, and Thunderbird 128.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox < 133, Firefox ESR < 128.5, Thunderbird < 133, and Thunderbird < 128.5.
{
"affected": [],
"aliases": [
"CVE-2024-11699"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-11-26T14:15:19Z",
"severity": "HIGH"
},
"details": "Memory safety bugs present in Firefox 132, Firefox ESR 128.4, and Thunderbird 128.4. Some of these bugs showed evidence of memory corruption and we presume that with enough effort some of these could have been exploited to run arbitrary code. This vulnerability affects Firefox \u003c 133, Firefox ESR \u003c 128.5, Thunderbird \u003c 133, and Thunderbird \u003c 128.5.",
"id": "GHSA-9g2q-259c-66mq",
"modified": "2025-11-04T00:32:08Z",
"published": "2024-11-26T15:31:02Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-11699"
},
{
"type": "WEB",
"url": "https://bugzilla.mozilla.org/buglist.cgi?bug_id=1880582%2C1929911"
},
{
"type": "WEB",
"url": "https://lists.debian.org/debian-lts-announce/2024/11/msg00029.html"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2024-63"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2024-64"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2024-67"
},
{
"type": "WEB",
"url": "https://www.mozilla.org/security/advisories/mfsa2024-68"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-9G7C-FG2X-X4JG
Vulnerability from github – Published: 2022-05-13 01:53 – Updated: 2022-05-13 01:53Eval injection in yzmphp/core/function/global.func.php in YzmCMS v3.7.1 allows remote attackers to achieve arbitrary code execution via PHP code in the POST data of an index.php?m=member&c=member_content&a=init request.
{
"affected": [],
"aliases": [
"CVE-2018-8756"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-03-18T06:29:00Z",
"severity": "HIGH"
},
"details": "Eval injection in yzmphp/core/function/global.func.php in YzmCMS v3.7.1 allows remote attackers to achieve arbitrary code execution via PHP code in the POST data of an index.php?m=member\u0026c=member_content\u0026a=init request.",
"id": "GHSA-9g7c-fg2x-x4jg",
"modified": "2022-05-13T01:53:48Z",
"published": "2022-05-13T01:53:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-8756"
},
{
"type": "WEB",
"url": "https://github.com/guiciwushuang/yzmcms/blob/master/yzmcms_eval_injection_chinese.pdf"
},
{
"type": "WEB",
"url": "https://github.com/guiciwushuang/yzmcms/blob/master/yzmcms_eval_injection_english.pdf"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-9G94-HXF9-JHQX
Vulnerability from github – Published: 2022-05-02 03:13 – Updated: 2022-05-02 03:13Microsoft Office PowerPoint 2002 SP3 allows remote attackers to execute arbitrary code via crafted sound data in a file that uses a PowerPoint 95 native file format, leading to improper "array indexing" and memory corruption, aka "PP7 Memory Corruption Vulnerability."
{
"affected": [],
"aliases": [
"CVE-2009-0225"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2009-05-12T22:30:00Z",
"severity": "HIGH"
},
"details": "Microsoft Office PowerPoint 2002 SP3 allows remote attackers to execute arbitrary code via crafted sound data in a file that uses a PowerPoint 95 native file format, leading to improper \"array indexing\" and memory corruption, aka \"PP7 Memory Corruption Vulnerability.\"",
"id": "GHSA-9g94-hxf9-jhqx",
"modified": "2022-05-02T03:13:41Z",
"published": "2022-05-02T03:13:41Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2009-0225"
},
{
"type": "WEB",
"url": "https://docs.microsoft.com/en-us/security-updates/securitybulletins/2009/ms09-017"
},
{
"type": "WEB",
"url": "https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5526"
},
{
"type": "WEB",
"url": "http://osvdb.org/54388"
},
{
"type": "WEB",
"url": "http://secunia.com/advisories/32428"
},
{
"type": "WEB",
"url": "http://www.securityfocus.com/bid/34880"
},
{
"type": "WEB",
"url": "http://www.securitytracker.com/id?1022205"
},
{
"type": "WEB",
"url": "http://www.us-cert.gov/cas/techalerts/TA09-132A.html"
},
{
"type": "WEB",
"url": "http://www.vupen.com/english/advisories/2009/1290"
},
{
"type": "WEB",
"url": "http://www.vupen.com/exploits/Microsoft_PowerPoint_Array_Indexing_Code_Execution_Exploit_MS09_017_1290125.php"
}
],
"schema_version": "1.4.0",
"severity": []
}
GHSA-9GCP-FWVG-C9V7
Vulnerability from github – Published: 2026-08-20 12:31 – Updated: 2026-08-20 12:31Subscriber Remote Code Execution (RCE) in Query Wrangler <= 1.5.57 versions.
{
"affected": [],
"aliases": [
"CVE-2026-73992"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2026-08-20T12:16:36Z",
"severity": "CRITICAL"
},
"details": "Subscriber Remote Code Execution (RCE) in Query Wrangler \u003c= 1.5.57 versions.",
"id": "GHSA-9gcp-fwvg-c9v7",
"modified": "2026-08-20T12:31:25Z",
"published": "2026-08-20T12:31:25Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-73992"
},
{
"type": "WEB",
"url": "https://patchstack.com/database/wordpress/plugin/query-wrangler/vulnerability/wordpress-query-wrangler-plugin-1-5-57-remote-code-execution-rce-vulnerability?_s_id=cve"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-9GH8-877R-G477
Vulnerability from github – Published: 2024-02-02 03:30 – Updated: 2024-02-12 15:35Before Beetl v3.15.13.RELEASE, the rendering template has a server-side template injection (SSTI) vulnerability. When the incoming template is controllable, it will be filtered by the DefaultNativeSecurityManager blacklist. Because blacklist filtering is not strict, the blacklist can be bypassed, leading to arbitrary code execution.
{
"affected": [
{
"package": {
"ecosystem": "Maven",
"name": "com.ibeetl:beetl-core"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "3.15.13.RELEASE"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2024-22533"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": true,
"github_reviewed_at": "2024-02-02T18:10:29Z",
"nvd_published_at": "2024-02-02T03:15:11Z",
"severity": "CRITICAL"
},
"details": "Before Beetl v3.15.13.RELEASE, the rendering template has a server-side template injection (SSTI) vulnerability. When the incoming template is controllable, it will be filtered by the DefaultNativeSecurityManager blacklist. Because blacklist filtering is not strict, the blacklist can be bypassed, leading to arbitrary code execution.",
"id": "GHSA-9gh8-877r-g477",
"modified": "2024-02-12T15:35:28Z",
"published": "2024-02-02T03:30:32Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-22533"
},
{
"type": "PACKAGE",
"url": "https://gitee.com/xiandafu/beetl"
},
{
"type": "WEB",
"url": "https://gitee.com/xiandafu/beetl/issues/I8RU01"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
],
"summary": "Beetl Server-Side Template Injection vulnerability"
}
GHSA-9GM2-28FM-HW6C
Vulnerability from github – Published: 2024-04-15 21:30 – Updated: 2024-07-08 15:31An issue discovered in silex technology DS-600 Firmware v.1.4.1 allows a remote attacker to edit device settings via the SAVE EEP_DATA command.
{
"affected": [],
"aliases": [
"CVE-2024-24486"
],
"database_specific": {
"cwe_ids": [
"CWE-284",
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-15T19:15:09Z",
"severity": "CRITICAL"
},
"details": "An issue discovered in silex technology DS-600 Firmware v.1.4.1 allows a remote attacker to edit device settings via the SAVE EEP_DATA command.",
"id": "GHSA-9gm2-28fm-hw6c",
"modified": "2024-07-08T15:31:54Z",
"published": "2024-04-15T21:30:45Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-24486"
},
{
"type": "WEB",
"url": "https://raw.githubusercontent.com/MostafaSoliman/Security-Advisories/master/CVE-2024-24486"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-9GM2-7MPC-RWC6
Vulnerability from github – Published: 2022-05-13 01:32 – Updated: 2022-05-13 01:32Remote Code Execution in the following products Hybrid Cloud Management Containerized Suite HCM2017.11, HCM2018.02, HCM2018.05, Operations Bridge Containerized Suite 2017.11, 2018.02, 2018.05, Data Center Automation Containerized Suite 2017.01 until 2018.05, Service Management Automation Suite 2017.11, 2018.02, 2018.05, Service Virtualization (SV) with floating licenses using Any version using APLS older than 10.7, Unified Functional Testing (UFT) with floating licenses using Any version using APLS older than 10.7, Network Virtualization (NV) with floating licenses using Any version using APLS older than 10.7 and Network Operations Management (NOM) Suite CDF 2017.11, 2018.02, 2018.05 will allow Remote Code Execution.
{
"affected": [],
"aliases": [
"CVE-2018-6499"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2018-08-30T21:29:00Z",
"severity": "CRITICAL"
},
"details": "Remote Code Execution in the following products Hybrid Cloud Management Containerized Suite HCM2017.11, HCM2018.02, HCM2018.05, Operations Bridge Containerized Suite 2017.11, 2018.02, 2018.05, Data Center Automation Containerized Suite 2017.01 until 2018.05, Service Management Automation Suite 2017.11, 2018.02, 2018.05, Service Virtualization (SV) with floating licenses using Any version using APLS older than 10.7, Unified Functional Testing (UFT) with floating licenses using Any version using APLS older than 10.7, Network Virtualization (NV) with floating licenses using Any version using APLS older than 10.7 and Network Operations Management (NOM) Suite CDF 2017.11, 2018.02, 2018.05 will allow Remote Code Execution.",
"id": "GHSA-9gm2-7mpc-rwc6",
"modified": "2022-05-13T01:32:00Z",
"published": "2022-05-13T01:32:00Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2018-6499"
},
{
"type": "WEB",
"url": "https://softwaresupport.softwaregrp.com/document/-/facetsearch/document/KM03236632?lang=en\u0026cc=us\u0026hpappid=206728_SSO_PRO"
},
{
"type": "WEB",
"url": "https://softwaresupport.softwaregrp.com/document/-/facetsearch/document/KM03236648"
},
{
"type": "WEB",
"url": "https://softwaresupport.softwaregrp.com/document/-/facetsearch/document/KM03236667"
},
{
"type": "WEB",
"url": "https://softwaresupport.softwaregrp.com/document/-/facetsearch/document/KM03236669"
},
{
"type": "WEB",
"url": "https://softwaresupport.softwaregrp.com/document/-/facetsearch/document/KM03236722"
},
{
"type": "WEB",
"url": "https://softwaresupport.softwaregrp.com/document/-/facetsearch/document/KM03236726"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-9GM8-6RQ9-QJ6F
Vulnerability from github – Published: 2025-12-16 18:31 – Updated: 2025-12-16 21:30Apache Commons Text versions prior to 1.10.0 included interpolation features that could be abused when applications passed untrusted input into the text-substitution API. Because some interpolators could trigger actions like executing commands or accessing external resources, an attacker could potentially achieve remote code execution. This vulnerability has been fully addressed in FileMaker Server 22.0.4.
{
"affected": [],
"aliases": [
"CVE-2025-46295"
],
"database_specific": {
"cwe_ids": [
"CWE-94"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-12-16T18:16:12Z",
"severity": "CRITICAL"
},
"details": "Apache Commons Text versions prior to 1.10.0 included interpolation features that could be abused when applications passed untrusted input into the text-substitution API. Because some interpolators could trigger actions like executing commands or accessing external resources, an attacker could potentially achieve remote code execution. This vulnerability has been fully addressed in FileMaker Server 22.0.4.",
"id": "GHSA-9gm8-6rq9-qj6f",
"modified": "2025-12-16T21:30:54Z",
"published": "2025-12-16T18:31:35Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2025-46295"
},
{
"type": "WEB",
"url": "https://support.claris.com/s/answerview?anum=000049059\u0026language=en_US"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
GHSA-9GMC-JQMH-3RVM
Vulnerability from github – Published: 2026-08-19 19:16 – Updated: 2026-08-19 19:16Copier: trust-prefix bypass via path traversal runs tasks unprompted
Summary
In copier >= 9.5.0, <= 9.15.1, the trust setting's prefix match
(copier/_settings.py) compares the template URL against a trusted prefix with
a raw str.startswith and no path normalization, while the URL is
normalized when the template is actually fetched (Path.resolve() for local
paths; libcurl dot-segment removal for https). A template reference that
textually starts with a trusted prefix but contains ..
(e.g. https://github.com/trusted-org/../attacker-org/repo.git) is therefore
granted trust yet resolves to a different, attacker-controlled template, whose
tasks / migrations / jinja_extensions then run without the --trust
prompt — arbitrary command execution. Likely CWE-22 (Improper Limitation of
a Pathname) in the trust check leading to CWE-94 (code execution).
Details
trust lets users mark template locations as trusted so copier skips the
unsafe-feature gate. A trailing / makes an entry a prefix match
(docs/settings.md: "Locations ending with / will be matched as prefixes,
trusting all templates from that location").
copier/_settings.py:141-146 (tag v9.15.1):
return any(
repository.startswith(_normalize(t))
if t.endswith("/")
else repository == _normalize(t)
for t in trust
)
_normalize only expands ~; it does not touch .. or collapse segments —
copier/_settings.py:149-152 (tag v9.15.1):
def _normalize(url: str) -> str:
if url.startswith("~"): # Only expand on str to avoid messing with URLs
url = expanduser(url) # noqa: PTH111
return url
This decision gates code execution — copier/_main.py:293 (tag v9.15.1):
if self.unsafe or is_trusted_repository(self.settings.trust, self.template.url):
return # skip the unsafe-feature check entirely
The chain: the trust comparison sees the raw URL, so
"https://github.com/safeorg/../evilorg/t.git".startswith("https://github.com/safeorg/")
is True; but the value copier hands to git/pathlib is normalized, so
the template actually loaded is evilorg/t (a different, attacker-owned org).
Trust is granted to a location the user never trusted, and _check_unsafe
returns early, so the malicious template's tasks execute with no prompt.
This is most acute on copier update, which reads _src_path from the
project's .copier-answers.yml (copier/_subproject.py) — i.e. an attacker who
hands you a project controls the URL that the trust check is applied to.
In-repo asymmetry that confirms the omission: copier consistently resolves
paths everywhere else it makes a security decision — Path.resolve() plus
is_relative_to(...) guards in _render_template, template_copy_root, and
_external_data — but not in the trust comparison.
PoC
Self-contained standalone script; runs against a clean, pinned PyPI install via
the real copier CLI only. Static by default (copier copy --pretend
reaches the trust decision but does not execute tasks); --prove-exec is an
opt-in supplementary run that fires an inert marker (echo + touch). The full
poc.py accompanies this report.
Build and run:
python -m venv venv && . venv/bin/activate
pip install "copier==9.15.1"
python poc.py # static proof (default)
python poc.py --prove-exec # also fire the inert marker
Observed output (copier 9.15.1):
== version proof ==
copier == 9.15.1
module : .../site-packages/copier/__init__.py
== inputs ==
trusted prefix (settings.yml): /tmp/copier_trust_poc_XXXX/trusted_templates/
control src (canonical) : /tmp/copier_trust_poc_XXXX/attacker/evil_template
exploit src (traversal) : /tmp/copier_trust_poc_XXXX/trusted_templates/../attacker/evil_template
both resolve to the SAME dir : True
exploit startswith trusted/ : True
minimal delta : exploit = '/tmp/copier_trust_poc_XXXX/trusted_templates/..' + '/attacker/evil_template'
== static proof (copier copy --pretend; payload NOT executed) ==
control (canonical, untrusted): exit=4 -> BLOCKED (UnsafeTemplateError)
exploit (trusted-prefix /..) : exit=0 -> TRUSTED, task reached
marker on disk after --pretend: False (expected False: --pretend does not run tasks)
--- copier's own output for the exploit (note the task it WOULD run) ---
| Copying from template version None
| create hello.txt
| > Running task 1 of 1: echo COPIER-TRUST-BYPASS-RCE-MARKER && touch COPIER_RCE_PROOF
== VERDICT ==
BYPASS CONFIRMED: identical template is refused by canonical path
(exit 4) yet granted trust via '<trusted>/..' traversal (exit 0),
so its tasks run with no --trust prompt.
== --prove-exec: running the exploit for real (inert marker) ==
| COPIER-TRUST-BYPASS-RCE-MARKER
| > Running task 1 of 1: echo COPIER-TRUST-BYPASS-RCE-MARKER && touch COPIER_RCE_PROOF
exit=0 marker file 'COPIER_RCE_PROOF' created: True
-> ARBITRARY COMMAND EXECUTED via a 'trusted' template, no --trust
The exploit is the same template as the control plus the minimal delta
<trusted_prefix>/... Deterministic: same input → same result. The PoC uses a
local trusted prefix for a self-contained, network-free run; the https case is
identical because git normalizes .. before the request — e.g.
git ls-remote "https://github.com/copier-org/../pallets/flask.git" emits
warning: redirecting to https://github.com/pallets/flask.git/ and returns
pallets/flask's refs, a different org than the trusted copier-org/.
Impact
A user who has configured a trusted prefix (a trailing-/ entry in
trust, a documented feature) no longer gets the unsafe-feature prompt for a
template that merely appears to live under that prefix. Any party who can
influence the template URL — most realistically the author of a project the
victim runs copier update on, since _src_path comes from that project's
.copier-answers.yml — can host the real template under a different
org/location reached via .. and have its tasks/migrations/
jinja_extensions execute arbitrary commands with no prompt. It fires on a
default, modern git for both local paths and https.
Proposed severity: High, comparable to the project's prior unsafe-template
advisory (GHSA-3xw7-v6cj-5q8h). Proposed CVSS v4 vector (maintainer to finalize;
AT:P reflects the required trusted-prefix configuration):
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H. Conservative
variant if you scope impact to the user account only (no host escape claim):
drop SC/SI/SA to N.
Recommended fix
Normalize both sides before comparing, instead of raw startswith. For
local entries, compare resolved absolute paths (Path(t).resolve() vs
Path(repository).resolve()) using segment containment / is_relative_to, the
pattern already used in _render_template and template_copy_root. For URL
entries, parse the URL and reject or collapse .././empty path segments
before the prefix test. As defense-in-depth, reject any _src_path read from an
answers file that contains .. segments after the scheme/host, since
legitimate template URLs never need them.
References
- CWE-22 — https://cwe.mitre.org/data/definitions/22.html
- CWE-94 — https://cwe.mitre.org/data/definitions/94.html
- Affected source (tag
v9.15.1):copier/_settings.py:141-146(prefix match),copier/_settings.py:149-152(_normalize),copier/_main.py:293(trust gate). - Documented prefix behavior:
docs/settings.md("Locations ending with/will be matched as prefixes"). https..normalization: libcurl removes dot segments by default (CURLOPT_PATH_AS_ISdefaults to off) — https://curl.se/libcurl/c/CURLOPT_PATH_AS_IS.html- Novelty: distinct from copier's published advisories, which concern filesystem
read/write traversal in rendered output; this is an authorization bypass in
the
trustsetting's URL matching. The flawed match is identical between releasedv9.15.1and currentmasterHEAD, and unchanged since the trust-prefix feature was introduced inv9.5.0(originallycopier/settings.py, commit71358ed; renamed tocopier/_settings.pyin the v9.12.0 refactor).
{
"affected": [
{
"database_specific": {
"last_known_affected_version_range": "\u003c= 9.15.1"
},
"package": {
"ecosystem": "PyPI",
"name": "copier"
},
"ranges": [
{
"events": [
{
"introduced": "9.5.0"
},
{
"fixed": "9.15.2"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [
"CVE-2026-53951"
],
"database_specific": {
"cwe_ids": [
"CWE-22",
"CWE-94"
],
"github_reviewed": true,
"github_reviewed_at": "2026-08-19T19:16:54Z",
"nvd_published_at": "2026-07-08T16:16:30Z",
"severity": "HIGH"
},
"details": "# Copier: trust-prefix bypass via path traversal runs tasks unprompted\n\n### Summary\n\nIn copier `\u003e= 9.5.0, \u003c= 9.15.1`, the `trust` setting\u0027s prefix match\n(`copier/_settings.py`) compares the template URL against a trusted prefix with\na raw `str.startswith` and **no path normalization**, while the URL *is*\nnormalized when the template is actually fetched (`Path.resolve()` for local\npaths; libcurl dot-segment removal for `https`). A template reference that\ntextually starts with a trusted prefix but contains `..`\n(e.g. `https://github.com/trusted-org/../attacker-org/repo.git`) is therefore\ngranted trust yet resolves to a different, attacker-controlled template, whose\n`tasks` / `migrations` / `jinja_extensions` then run **without the `--trust`\nprompt** \u2014 arbitrary command execution. Likely **CWE-22 (Improper Limitation of\na Pathname)** in the trust check leading to **CWE-94 (code execution)**.\n\n### Details\n\n`trust` lets users mark template locations as trusted so copier skips the\nunsafe-feature gate. A trailing `/` makes an entry a **prefix** match\n(`docs/settings.md`: *\"Locations ending with `/` will be matched as prefixes,\ntrusting all templates from that location\"*).\n\n`copier/_settings.py:141-146` (tag `v9.15.1`):\n\n```python\n return any(\n repository.startswith(_normalize(t))\n if t.endswith(\"/\")\n else repository == _normalize(t)\n for t in trust\n )\n```\n\n`_normalize` only expands `~`; it does **not** touch `..` or collapse segments \u2014\n`copier/_settings.py:149-152` (tag `v9.15.1`):\n\n```python\ndef _normalize(url: str) -\u003e str:\n if url.startswith(\"~\"): # Only expand on str to avoid messing with URLs\n url = expanduser(url) # noqa: PTH111\n return url\n```\n\nThis decision gates code execution \u2014 `copier/_main.py:293` (tag `v9.15.1`):\n\n```python\n if self.unsafe or is_trusted_repository(self.settings.trust, self.template.url):\n return # skip the unsafe-feature check entirely\n```\n\nThe chain: the trust comparison sees the **raw** URL, so\n`\"https://github.com/safeorg/../evilorg/t.git\".startswith(\"https://github.com/safeorg/\")`\nis `True`; but the value copier hands to `git`/`pathlib` is **normalized**, so\nthe template actually loaded is `evilorg/t` (a different, attacker-owned org).\nTrust is granted to a location the user never trusted, and `_check_unsafe`\nreturns early, so the malicious template\u0027s tasks execute with no prompt.\n\nThis is most acute on `copier update`, which reads `_src_path` from the\nproject\u0027s `.copier-answers.yml` (`copier/_subproject.py`) \u2014 i.e. an attacker who\nhands you a project controls the URL that the trust check is applied to.\n\nIn-repo asymmetry that confirms the omission: copier consistently resolves\npaths *everywhere else* it makes a security decision \u2014 `Path.resolve()` plus\n`is_relative_to(...)` guards in `_render_template`, `template_copy_root`, and\n`_external_data` \u2014 but not in the trust comparison.\n\n### PoC\n\nSelf-contained standalone script; runs against a clean, pinned PyPI install via\nthe real `copier` CLI only. **Static by default** (`copier copy --pretend`\nreaches the trust decision but does not execute tasks); `--prove-exec` is an\nopt-in supplementary run that fires an inert marker (`echo` + `touch`). The full\n`poc.py` accompanies this report.\n\nBuild and run:\n\n```bash\npython -m venv venv \u0026\u0026 . venv/bin/activate\npip install \"copier==9.15.1\"\npython poc.py # static proof (default)\npython poc.py --prove-exec # also fire the inert marker\n```\n\nObserved output (`copier 9.15.1`):\n\n```\n== version proof ==\n copier == 9.15.1\n module : .../site-packages/copier/__init__.py\n\n== inputs ==\n trusted prefix (settings.yml): /tmp/copier_trust_poc_XXXX/trusted_templates/\n control src (canonical) : /tmp/copier_trust_poc_XXXX/attacker/evil_template\n exploit src (traversal) : /tmp/copier_trust_poc_XXXX/trusted_templates/../attacker/evil_template\n both resolve to the SAME dir : True\n exploit startswith trusted/ : True\n minimal delta : exploit = \u0027/tmp/copier_trust_poc_XXXX/trusted_templates/..\u0027 + \u0027/attacker/evil_template\u0027\n\n== static proof (copier copy --pretend; payload NOT executed) ==\n control (canonical, untrusted): exit=4 -\u003e BLOCKED (UnsafeTemplateError)\n exploit (trusted-prefix /..) : exit=0 -\u003e TRUSTED, task reached\n marker on disk after --pretend: False (expected False: --pretend does not run tasks)\n\n --- copier\u0027s own output for the exploit (note the task it WOULD run) ---\n | Copying from template version None\n | create hello.txt\n | \u003e Running task 1 of 1: echo COPIER-TRUST-BYPASS-RCE-MARKER \u0026\u0026 touch COPIER_RCE_PROOF\n\n== VERDICT ==\n BYPASS CONFIRMED: identical template is refused by canonical path\n (exit 4) yet granted trust via \u0027\u003ctrusted\u003e/..\u0027 traversal (exit 0),\n so its tasks run with no --trust prompt.\n\n== --prove-exec: running the exploit for real (inert marker) ==\n | COPIER-TRUST-BYPASS-RCE-MARKER\n | \u003e Running task 1 of 1: echo COPIER-TRUST-BYPASS-RCE-MARKER \u0026\u0026 touch COPIER_RCE_PROOF\n exit=0 marker file \u0027COPIER_RCE_PROOF\u0027 created: True\n -\u003e ARBITRARY COMMAND EXECUTED via a \u0027trusted\u0027 template, no --trust\n```\n\nThe exploit is the same template as the control plus the minimal delta\n`\u003ctrusted_prefix\u003e/..`. Deterministic: same input \u2192 same result. The PoC uses a\nlocal trusted prefix for a self-contained, network-free run; the `https` case is\nidentical because git normalizes `..` before the request \u2014 e.g.\n`git ls-remote \"https://github.com/copier-org/../pallets/flask.git\"` emits\n`warning: redirecting to https://github.com/pallets/flask.git/` and returns\n`pallets/flask`\u0027s refs, a different org than the trusted `copier-org/`.\n\n### Impact\n\nA user who has configured a trusted **prefix** (a trailing-`/` entry in\n`trust`, a documented feature) no longer gets the unsafe-feature prompt for a\ntemplate that merely *appears* to live under that prefix. Any party who can\ninfluence the template URL \u2014 most realistically the author of a project the\nvictim runs `copier update` on, since `_src_path` comes from that project\u0027s\n`.copier-answers.yml` \u2014 can host the real template under a different\norg/location reached via `..` and have its `tasks`/`migrations`/\n`jinja_extensions` execute arbitrary commands with no prompt. It fires on a\ndefault, modern git for both local paths and `https`.\n\nProposed severity: **High**, comparable to the project\u0027s prior unsafe-template\nadvisory (GHSA-3xw7-v6cj-5q8h). Proposed CVSS v4 vector (maintainer to finalize;\n`AT:P` reflects the required trusted-prefix configuration):\n`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H`. Conservative\nvariant if you scope impact to the user account only (no host escape claim):\ndrop `SC/SI/SA` to `N`.\n\n### Recommended fix\n\nNormalize **both** sides before comparing, instead of raw `startswith`. For\nlocal entries, compare resolved absolute paths (`Path(t).resolve()` vs\n`Path(repository).resolve()`) using segment containment / `is_relative_to`, the\npattern already used in `_render_template` and `template_copy_root`. For URL\nentries, parse the URL and reject or collapse `..`/`.`/empty path segments\nbefore the prefix test. As defense-in-depth, reject any `_src_path` read from an\nanswers file that contains `..` segments after the scheme/host, since\nlegitimate template URLs never need them.\n\n### References\n\n- CWE-22 \u2014 https://cwe.mitre.org/data/definitions/22.html\n- CWE-94 \u2014 https://cwe.mitre.org/data/definitions/94.html\n- Affected source (tag `v9.15.1`): `copier/_settings.py:141-146` (prefix match),\n `copier/_settings.py:149-152` (`_normalize`), `copier/_main.py:293` (trust gate).\n- Documented prefix behavior: `docs/settings.md` (\"Locations ending with `/`\n will be matched as prefixes\").\n- `https` `..` normalization: libcurl removes dot segments by default\n (`CURLOPT_PATH_AS_IS` defaults to off) \u2014 https://curl.se/libcurl/c/CURLOPT_PATH_AS_IS.html\n- Novelty: distinct from copier\u0027s published advisories, which concern filesystem\n read/write traversal in rendered output; this is an authorization bypass in\n the `trust` setting\u0027s URL matching. The flawed match is identical between\n released `v9.15.1` and current `master` HEAD, and unchanged since the\n trust-prefix feature was introduced in `v9.5.0` (originally `copier/settings.py`,\n commit `71358ed`; renamed to `copier/_settings.py` in the v9.12.0 refactor).",
"id": "GHSA-9gmc-jqmh-3rvm",
"modified": "2026-08-19T19:16:54Z",
"published": "2026-08-19T19:16:54Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/copier-org/copier/security/advisories/GHSA-9gmc-jqmh-3rvm"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-53951"
},
{
"type": "PACKAGE",
"url": "https://github.com/copier-org/copier"
},
{
"type": "WEB",
"url": "https://github.com/copier-org/copier/releases/tag/v9.15.2"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H",
"type": "CVSS_V4"
}
],
"summary": "Copier has a trust-prefix bypass via path traversal that runs tasks unprompted"
}
Mitigation
Strategy: Refactoring
Refactor your program so that you do not have to dynamically generate code.
Mitigation
- Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
- Examples include the Unix chroot jail and AppArmor. In general, managed code may provide some protection.
- This may not be a feasible solution, and it only limits the impact to the operating system; the rest of your application may still be subject to compromise.
- Be careful to avoid CWE-243 and other weaknesses related to jails.
Mitigation MIT-5
Strategy: Input Validation
- Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
- When performing input validation, consider all potentially relevant properties, including length, type of input, the full range of acceptable values, missing or extra inputs, syntax, consistency across related fields, and conformance to business rules. As an example of business rule logic, "boat" may be syntactically valid because it only contains alphanumeric characters, but it is not valid if the input is only expected to contain colors such as "red" or "blue."
- Do not rely exclusively on looking for malicious or malformed inputs. This is likely to miss at least one undesirable input, especially if the code's environment changes. This can give attackers enough room to bypass the intended validation. However, denylists can be useful for detecting potential attacks or determining which inputs are so malformed that they should be rejected outright.
- To reduce the likelihood of code injection, use stringent allowlists that limit which constructs are allowed. If you are dynamically constructing code that invokes a function, then verifying that the input is alphanumeric might be insufficient. An attacker might still be able to reference a dangerous function that you did not intend to allow, such as system(), exec(), or exit().
Mitigation
Use dynamic tools and techniques that interact with the product using large test suites with many diverse inputs, such as fuzz testing (fuzzing), robustness testing, and fault injection. The product's operation may slow down, but it should not become unstable, crash, or generate incorrect results.
Mitigation MIT-32
Strategy: Compilation or Build Hardening
Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
Mitigation MIT-32
Strategy: Environment Hardening
Run the code in an environment that performs automatic taint propagation and prevents any command execution that uses tainted variables, such as Perl's "-T" switch. This will force the program to perform validation steps that remove the taint, although you must be careful to correctly validate your inputs so that you do not accidentally mark dangerous inputs as untainted (see CWE-183 and CWE-184).
Mitigation
For Python programs, it is frequently encouraged to use the ast.literal_eval() function instead of eval, since it is intentionally designed to avoid executing code. However, an adversary could still cause excessive memory or stack consumption via deeply nested structures [REF-1372], so the python documentation discourages use of ast.literal_eval() on untrusted data [REF-1373].
CAPEC-242: Code Injection
An adversary exploits a weakness in input validation on the target to inject new code into that which is currently executing. This differs from code inclusion in that code inclusion involves the addition or replacement of a reference to a code file, which is subsequently loaded by the target and used as part of the code of some application.
CAPEC-35: Leverage Executable Code in Non-Executable Files
An attack of this type exploits a system's trust in configuration and resource files. When the executable loads the resource (such as an image file or configuration file) the attacker has modified the file to either execute malicious code directly or manipulate the target process (e.g. application server) to execute based on the malicious configuration parameters. Since systems are increasingly interrelated mashing up resources from local and remote sources the possibility of this attack occurring is high.
CAPEC-77: Manipulating User-Controlled Variables
This attack targets user controlled variables (DEBUG=1, PHP Globals, and So Forth). An adversary can override variables leveraging user-supplied, untrusted query variables directly used on the application server without any data sanitization. In extreme cases, the adversary can change variables controlling the business logic of the application. For instance, in languages like PHP, a number of poorly set default configurations may allow the user to override variables.