CVE-2026-44699: From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the
Affects libjwtSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical · fixed in 3.3.3 : patch libjwt as a priority.
Data as of 13 Nov 2026, 13:10 UTC
- Patch
- Available – fixed in 3.3.3
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 15 May 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 13 Nov 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.10libjwtpkg:deb/ubuntu/libjwt?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.10libjwt3pkg:deb/ubuntu/libjwt3?arch=source&distro=stonkingOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlibjwtpkg:deb/ubuntu/libjwt?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlibjwt3pkg:deb/ubuntu/libjwt3?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 25.10libjwtpkg:deb/ubuntu/libjwt?arch=source&distro=questingOther threats | Affected
| Fixed in– |
Ubuntu 24.04 LTSlibjwtpkg:deb/ubuntu/libjwt?arch=source&distro=nobleOther 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
Upgrade libjwt to version 3.3.3 or later, where this vulnerability is fixed. No other mitigation is indicated or required by the vendor advisory.
Description
LibJWT versions from 3.0.0 to 3.3.2 have a vulnerability where RSA JSON Web Keys (JWKs) missing the 'alg' parameter are accepted as verification keys for HS256/HS384/HS512 tokens. This leads to HMAC verification using a zero-length key in the OpenSSL backend, allowing attackers to forge valid JWTs without the secret or RSA private key. The issue is fixed in version 3.3.3.