Pyjwt: From 2.13.0 until 2.14.0, HMACAlgorithm.from_jwk is affected because PyJWK verification path used the decoded
Affects pyjwtSource GCVE Database
Not known to be exploited · CVSS 7.4 High · fixed in 2.13.0-1ubuntu1 : patch pyjwt soon.
Data as of 27 Oct 2026, 14:30 UTC
- Patch
- Available – fixed in 2.13.0-1ubuntu1, 2.10.1-4ubuntu1.2
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 28 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: 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 26 Oct 2026.
What to do
Upgrade the Ubuntu pyjwt to 2.13.0-1ubuntu1 (package) or 2.10.1-4ubuntu1.2 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10pyjwtpkg:deb/ubuntu/pyjwt?arch=source&distro=stonkingOther threats | Affected
| Fixed in
|
Ubuntu 26.04 LTSpyjwtpkg:deb/ubuntu/pyjwt?arch=source&distro=resoluteOther 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 and has been released in PyJWT version 2.14.0. Users should update to this version or later. Ubuntu users should apply the security updates provided in packages python3-jwt 2.13.0-1ubuntu1 or python3-jwt 2.10.1-4ubuntu1.2 as appropriate. Standard system updates will apply these fixes. No additional mitigation actions are required beyond applying these updates.
Description
PyJWT versions from 2.13.0 until 2.14.0 contain a vulnerability in the HMACAlgorithm.from_jwk function where the verification path uses a decoded key without proper prepare_key validation. This flaw allows an attacker to exploit a trusted JWK Set containing an oct entry with an empty key value, enabling the signing of HMAC tokens with a zero-length key that PyJWT accepts. As a result, attackers can forge tokens with arbitrary authenticated claims. The issue is fixed in PyJWT version 2.14.0.
References
- ubuntu.com/security/CVE-2026-102266 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-102266 (opens in a new tab)
- github.com/jpadilla/pyjwt/security/advisories/GHSA-9j54-fg26-wv3r (opens in a new tab)
- github.com/jpadilla/pyjwt/commit/f91ed44dd65baaf457f4b3353ed35e98a753934c (opens in a new tab)
- github.com/jpadilla/pyjwt/releases/tag/2.14.0 (opens in a new tab)
- ubuntu.com/security/notices/USN-8916-2 (opens in a new tab)
- ubuntu.com/security/notices/USN-8916-1 (opens in a new tab)