s3ql · OAuthLib: Token grants can use attacker-supplied client_id for authorization after authenticating a different client
Affects s3qlSource GCVE Database
Not known to be exploited · CVSS 8.4 High : upgrade to 6.3.1_1 or 3.8.1 soon.
Data as of 31 Oct 2026, 16:36 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 8.4 |
|---|
- Patch
- Available – fixed in 6.3.1_1, 3.8.1
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:H/SI:H/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade s3ql to 6.3.1_1 or 3.8.1.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Homebrews3qlpkg:brew/s3qlOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available in OAuthlib versions 3.8.1 and 6.3.1_1. Users should upgrade to these versions or later to remediate the vulnerability. Deployments should also review their RequestValidator implementations to ensure authorization decisions are based on the authenticated client object rather than the client_id argument passed by OAuthlib. No additional mitigation is required if the validator ignores the client_id argument and authorizes solely from request.client.
Description
OAuthlib versions prior to 3.8.1 and 6.3.1_1 contain a vulnerability in token grant handlers where an authenticated low-privilege client can supply a different client_id in the token request body. This causes grant and scope validation to be performed under the attacker-supplied client_id rather than the authenticated client's identity. The issue affects the client_credentials and password grant flows and can lead to unauthorized token issuance with elevated scopes or grants.
References
- github.com/oauthlib/oauthlib/security/advisories/GHSA-7984-qgvg-3j9c (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-118669 (opens in a new tab)
- github.com/oauthlib/oauthlib/pull/920 (opens in a new tab)
- github.com/oauthlib/oauthlib/commit/c951a1d09f99f14e3240973fa83c4f4287d4753d (opens in a new tab)
- github.com/oauthlib/oauthlib (opens in a new tab)
- github.com/oauthlib/oauthlib/releases/tag/v4.0.0 (opens in a new tab)