Python oauthlib: Prior to 4.0.0, the client_credentials and Resource Owner Password Credentials token grant handlers
Affects python-oauthlibSource GCVE Database
Not known to be exploited · CVSS 8.4 High · fixed in 4.0.0 : patch python-oauthlib soon.
Data as of 5 Nov 2026, 12:35 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 8.4 |
|---|
- Patch
- Available – fixed in 4.0.0
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 5 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10python-oauthlibpkg:deb/ubuntu/python-oauthlib?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSpython-oauthlibpkg:deb/ubuntu/python-oauthlib?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSpython-oauthlibpkg:deb/ubuntu/python-oauthlib?arch=source&distro=nobleOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSpython-oauthlibpkg:deb/ubuntu/python-oauthlib?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSpython-oauthlibpkg:deb/ubuntu/python-oauthlib?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSpython-oauthlibpkg:deb/ubuntu/python-oauthlib?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
Description
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.
References
- ubuntu.com/security/CVE-2026-118669 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-118669 (opens in a new tab)
- github.com/oauthlib/oauthlib/commit/c951a1d09f99f14e3240973fa83c4f4287d4753d (opens in a new tab)
- github.com/oauthlib/oauthlib/pull/920 (opens in a new tab)
- github.com/oauthlib/oauthlib/releases/tag/v4.0.0 (opens in a new tab)
- github.com/oauthlib/oauthlib/security/advisories/GHSA-7984-qgvg-3j9c (opens in a new tab)