CVE catalog
CVE-2026-44699
LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backe
- Severity
- Critical · CVSS 9.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.21% · Oct 25, 2026
LibJWT is a C JSON Web Token Library. From 3.0.0 to 3.3.2, libjwt accepts an RSA JWK that does not contain an alg parameter as the verification key for an HS256/HS384/HS512 token. In the OpenSSL backend, this causes HMAC verification to run with a zero-length key, so an attacker can forge a valid JWT without knowing any secret or RSA private key. This is an algorithm-confusion authentication bypass. It affects applications that load RSA keys from JWKS where alg is omitted, which is valid JWK syntax and common in real deployments, and then choose the verification algorithm from the JWT header, for example in a kid lookup callback. This vulnerability is fixed in 3.3.3.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | libjwt | sid | 1.17.2-1 | not affected |
| Debian | libjwt | forky | 1.17.2-1 | not affected |
| Debian | libjwt | trixie | 1.17.2-1 | not affected |
| Debian | libjwt | bookworm | 1.10.2-1+deb12u1 | not affected |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | libjwt | source | sid | Not affected | unimportant | Not reported | Not reported |
| Debian | libjwt | source | forky | Not affected | unimportant | Not reported | Not reported |
| Debian | libjwt | source | trixie | Not affected | unimportant | Not reported | Not reported |
| Debian | libjwt | source | bookworm | Not affected | unimportant | Not reported | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libjwt0]Not affected
Source package: [libjwt]
Details (2)
1.10.2-1+deb12u1· amd64 · bookwormNot affected
nvd · libjwt · debian · bookworm
1.10.2-1+deb12u1· arm64 · bookwormNot affected
nvd · libjwt · debian · bookworm
- [libjwt-dev]Not affected
Source package: [libjwt]
Details (2)
1.10.2-1+deb12u1· amd64 · bookwormNot affected
nvd · libjwt · debian · bookworm
1.10.2-1+deb12u1· arm64 · bookwormNot affected
nvd · libjwt · debian · bookworm
- [libjwt-gnutls0]Not affected
Source package: [libjwt]
Details (2)
1.10.2-1+deb12u1· amd64 · bookwormNot affected
nvd · libjwt · debian · bookworm
1.10.2-1+deb12u1· arm64 · bookwormNot affected
nvd · libjwt · debian · bookworm
- [libjwt-gnutls-dev]Not affected
Source package: [libjwt]
Details (2)
1.10.2-1+deb12u1· amd64 · bookwormNot affected
nvd · libjwt · debian · bookworm
1.10.2-1+deb12u1· arm64 · bookwormNot affected
nvd · libjwt · debian · bookworm
Observed:
References
- [https://github.com/benmcollins/libjwt/security/advisories/GHSA-q843-6q5f-w55g]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-44699]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-44699]
- [https://security-tracker.debian.org/tracker/CVE-2026-44699]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44699.json]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]