Vulnerability-Lookup

RHSA-2026:99167

Vulnerability from csaf_redhat - Published: 2026-11-12 01:32 - Updated: 2026-11-13 13:03

Summary

Red Hat Security Advisory: python-oauthlib security update

Severity

Important

Notes

Topic: An update for python-oauthlib is now available for Red Hat Enterprise Linux 9.8 Extended Update Support. Red Hat Product Security has rated this update as having a security impact of Important. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Details: Python is an interpreted, interactive, object-oriented programming language, which includes modules, classes, exceptions, very high level dynamic data types and dynamic typing. Python supports interfaces to many system calls and libraries, as well as to various windowing systems. Security Fix(es): * oauthlib: oauthlib: privilege escalation via client identity confusion in token grant handlers (CVE-2026-118669) For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Terms of Use: This content is licensed under the Creative Commons Attribution 4.0 International License (https://creativecommons.org/licenses/by/4.0/). If you distribute this content, or a modified version of it, you must provide attribution to Red Hat Inc. and provide a link to the original.

CVE-2026-118669

A flaw was found in oauthlib. In certain token grant flows, the authorization system can authenticate an incoming client while retaining a different, client-supplied identifier for permission and scope validation. A remote, authenticated attacker with lower privileges can exploit this inconsistency by submitting another client's identifier during token requests. This flaw leads to privilege escalation, potentially allowing the attacker to obtain access tokens with unauthorized permissions and scopes associated with another client.

8.1 (High)


                
                  CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N

CWE-807 - Reliance on Untrusted Inputs in a Security Decision

Affected products

Fixed 2 products

Product	Identifier	Version	Remediation
Unresolved product id: AppStream-9.8.0.Z.EUS:python-oauthlib-0:3.1.1-5.el9_8.1.src		—	Vendor Fix fix
Unresolved product id: AppStream-9.8.0.Z.EUS:python3-oauthlib-0:3.1.1-5.el9_8.1.noarch		—	Vendor Fix fix

Threats

Impact Important

References

12 references

URL	Category
https://access.redhat.com/errata/RHSA-2026:99167	self
https://access.redhat.com/security/updates/classi…	external
https://bugzilla.redhat.com/show_bug.cgi?id=2563201	external
https://security.access.redhat.com/data/csaf/v2/a…	self
https://access.redhat.com/security/cve/CVE-2026-118669	self
https://bugzilla.redhat.com/show_bug.cgi?id=2563201	external
https://www.cve.org/CVERecord?id=CVE-2026-118669	external
https://nvd.nist.gov/vuln/detail/CVE-2026-118669	external
https://github.com/oauthlib/oauthlib/commit/c951a…	external
https://github.com/oauthlib/oauthlib/pull/920	external
https://github.com/oauthlib/oauthlib/releases/tag…	external
https://github.com/oauthlib/oauthlib/security/adv…	external

JSON

To clipboard

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          "title": "Vulnerability description"
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          "text": "oauthlib: oauthlib: privilege escalation via client identity confusion in token grant handlers",
          "title": "Vulnerability summary"
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        {
          "category": "other",
          "text": "This vulnerability is rated as an Important severity for Red Hat products because an authenticated client with low privileges can obtain access tokens under a different identity over the network, leading to significant privilege escalation without requiring user interaction. The exposure specifically impacts deployments where the server application relies on the submitted client identifier parameter during scope or grant checks instead of the authenticated client object. Workloads that do not act as an OAuth2 token endpoint or that enforce scope authorization solely from the authenticated entity remain unaffected.",
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}

CVE-2026-118669 (GCVE-0-2026-118669)

Vulnerability from cvelistv5 – Published: 2026-10-28 21:09 – Updated: 2026-11-03 13:38

Title

OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client

Summary

OAuthLib is an implementation of the OAuth request-signing logic for Python 3.6+. Prior to 4.0.0, the client_credentials and Resource Owner Password Credentials token grant handlers can authenticate request.client as one confidential client while retaining an attacker-supplied request.client_id for validate_grant_type and validate_scopes. A lower-privilege authenticated client can therefore cause grant and scope authorization to use another client's identity when an application validator relies on the documented client_id argument, potentially issuing tokens with unauthorized grants or scopes. Validators that authorize exclusively from request.client may not be affected. This issue is fixed in version 4.0.0.

Severity

8.4 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-11-03 13:38 UTC

CWE

CWE-863 - Incorrect Authorization

Assigner

GitHub_M CNA under the mitre root

CNA scorecard C 72/100 over 7886 records in the last 180 days details

References

4 references

URL	Tags
https://github.com/oauthlib/oauthlib/security/adv…	x_refsource_CONFIRM
https://github.com/oauthlib/oauthlib/pull/920	x_refsource_MISC
https://github.com/oauthlib/oauthlib/commit/c951a…	x_refsource_MISC
https://github.com/oauthlib/oauthlib/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
oauthlib	oauthlib	Affected: < 4.0.0

Show details on NVD website

JSON

To clipboard

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        "metrics": [
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            "other": {
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                "id": "CVE-2026-118669",
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                "timestamp": "2026-11-03T13:38:15.438408Z",
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    ],
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      ],
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

Order JSON

How durations are calculated

Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.

Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.

Publication & reservation Sightings KEV catalogs Other timestamps

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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

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