CVE catalog
CVE-2026-48523
PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. T
- Severity
- High · CVSS 7.4
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.13% · Oct 25, 2026
PyJWT is a JSON Web Token implementation in Python. From 2.9.0 to 2.12.1, there is a verifier-side algorithm allow-list bypass when jwt.decode() or jwt.decode_complete() are called with a PyJWK key. The token header alg is checked against the caller-supplied algorithms allow-list, but signature verification is performed with the algorithm bound to the PyJWK object instead of the header algorithm. An attacker who controls a registered JWK/JWKS private key can sign with a disallowed algorithm, advertise an allowed algorithm in the JWT header, and still be accepted. The issue affects the documented PyJWKClient.get_signing_key_from_jwt(...) flow. This vulnerability is fixed in 2.13.0.
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 | pyjwt | sid | 2.15.1-1 | fixed |
| Debian | pyjwt | forky | 2.15.1-1 | fixed |
| Debian | pyjwt | trixie | 2.10.1-2+deb13u1 | vulnerable |
| Debian | pyjwt | trixie-security | 2.10.1-2+deb13u1 | vulnerable |
| Debian | pyjwt | bookworm | 2.6.0-1+deb12u1 | not affected |
| Debian | pyjwt | bookworm-security | 2.6.0-1+deb12u1 | not affected |
| Cpe | pyjwt | Not reported | 2.12.1 | fixed |
| PyPI | pyjwt | Not reported | 2.13.0 | fixed |
| PyPI | pyjwt | Not reported | 2.12.1 | fixed |
| Cpe | pyjwt | Not reported | 2.13.0 | fixed |
| Ubuntu | pyjwt | noble | 2.7.0-1ubuntu0.2 | fixed |
| Ubuntu | python3-jwt | noble | 2.7.0-1ubuntu0.2 | fixed |
| Ubuntu | pyjwt | 25.10 | 2.10.1-2 | vulnerable |
| Ubuntu | pyjwt | 25.10 | 2.10.1-2ubuntu0.1 | vulnerable |
| Ubuntu | pyjwt | 26.04 | 2.10.1-2 | vulnerable |
| Ubuntu | pyjwt | 26.04 | 2.10.1-3 | vulnerable |
| Ubuntu | pyjwt | 26.04 | 2.10.1-3build1 | vulnerable |
| Ubuntu | pyjwt | 26.04 | 2.10.1-4 | vulnerable |
| Ubuntu | pyjwt | 26.04 | 2.10.1-4ubuntu1 | vulnerable |
| Ubuntu | pyjwt | 26.04 | 2.10.1-4ubuntu1.1 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | pyjwt | source | sid | 2.13.0-1 | not yet assigned | Not reported | [1138191] |
| Debian | pyjwt | source | forky | 2.13.0-1 | not yet assigned | Not reported | [1138191] |
| Debian | pyjwt | source | trixie | (unfixed) | not yet assigned | Not reported | [1138191] |
| Debian | pyjwt | source | bookworm | Not affected | unimportant | Not reported | [1138191] |
| Cpe | pyjwt | cpe | Not reported | 2.12.1 | Not reported | Not reported | Not reported |
| PyPI | pyjwt | PyPI | Not reported | 2.13.0 | Not reported | GHSA-JQ35-7PRP-9V3F | Not reported |
| PyPI | pyjwt | PyPI | Not reported | 2.12.1 | Not reported | Not reported | Not reported |
| Cpe | pyjwt | cpe | Not reported | 2.13.0 | Not reported | NVD-CVE-2026-48523 | Not reported |
| Ubuntu | pyjwt | deb | noble | 2.7.0-1ubuntu0.2 | Not reported | Not reported | Not reported |
| Ubuntu | python3-jwt | deb | noble | 2.7.0-1ubuntu0.2 | Not reported | Not reported | Not reported |
| Ubuntu | pyjwt | deb | 26.04 | 2.10.1-4ubuntu1.1 | Not reported | UBUNTU-CVE-2026-48523 | Not reported |
Notes
[trixie] pyjwt: Minor issue
OpenFactory catalog packages
[Debian 13 (Trixie)]
- [python3-jwt]Affected
Source package: [pyjwt]
Details (4)
2.10.1-2+deb13u1· all · trixieAffected
nvd · pyjwt · debian · 13
2.10.1-2+deb13u1· all · trixieAffected
nvd · pyjwt · debian · 13
2.10.1-2+deb13u1· all · trixie-securityAffected
nvd · pyjwt · debian · 13
2.10.1-2+deb13u1· all · trixie-securityAffected
nvd · pyjwt · debian · 13
- [python-jwt-doc]Affected
Source package: [pyjwt]
Details (4)
2.10.1-2+deb13u1· all · trixieAffected
nvd · pyjwt · debian · 13
2.10.1-2+deb13u1· all · trixieAffected
nvd · pyjwt · debian · 13
2.10.1-2+deb13u1· all · trixie-securityAffected
nvd · pyjwt · debian · 13
2.10.1-2+deb13u1· all · trixie-securityAffected
nvd · pyjwt · debian · 13
[Debian 12 (Bookworm)]
- [python3-jwt]Not affected
Source package: [pyjwt]
Details (4)
2.6.0-1+deb12u1· all · bookwormNot affected
nvd · pyjwt · debian · bookworm
2.6.0-1+deb12u1· all · bookwormNot affected
nvd · pyjwt · debian · bookworm
2.6.0-1+deb12u1· all · bookworm-securityNot affected
nvd · pyjwt · debian · bookworm
2.6.0-1+deb12u1· all · bookworm-securityNot affected
nvd · pyjwt · debian · bookworm
Observed:
References
- [https://ftp.suse.com/pub/projects/security/]
- [https://github.com/jpadilla/pyjwt/security/advisories/GHSA-jq35-7prp-9v3f]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-48523]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-48523]
- [https://osv.dev/vulnerability/GHSA-jq35-7prp-9v3f]
- [https://osv.dev/vulnerability/UBUNTU-CVE-2026-48523]
- [https://security-tracker.debian.org/tracker/CVE-2026-48523]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-48523.json]
- [https://ubuntu.com/security/notices/USN-8823-1]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]