CVE catalog
CVE-2026-28498
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a library-level vulnerability was identified in the Authlib Python library concerning the validation
- 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
- 0.24% · Oct 25, 2026
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a library-level vulnerability was identified in the Authlib Python library concerning the validation of OpenID Connect (OIDC) ID Tokens. Specifically, the internal hash verification logic (_verify_hash) responsible for validating the at_hash (Access Token Hash) and c_hash (Authorization Code Hash) claims exhibits a fail-open behavior when encountering an unsupported or unknown cryptographic algorithm. This flaw allows an attacker to bypass mandatory integrity protections by supplying a forged ID Token with a deliberately unrecognized alg header parameter. The library intercepts the unsupported state and silently returns True (validation passed), inherently violating fundamental cryptographic design principles and direct OIDC specifications. This issue has been patched in version 1.6.9.
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 | python-authlib | sid | 1.7.2-2 | fixed |
| Debian | python-authlib | forky | 1.7.2-2 | fixed |
| Debian | python-authlib | trixie | 1.6.0-1+deb13u1 | vulnerable |
| Debian | python-authlib | bookworm | 1.2.0-1+deb12u1 | vulnerable |
| Debian | python-authlib | bookworm-security | 1.2.0-1+deb12u2 | fixed |
| Pip | authlib | Not reported | 1.6.9 | fixed |
| Cpe | python-authlib | Not reported | Not reported | vulnerable |
| Cpe | python-authlib | Not reported | 1.3.0-1ubuntu0.1~esm2 | fixed |
| Cpe | python-authlib-doc | Not reported | 1.3.0-1ubuntu0.1~esm2 | fixed |
| Cpe | python3-authlib | Not reported | 1.3.0-1ubuntu0.1~esm2 | fixed |
| Cpe | authlib | Not reported | 1.6.9 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | python-authlib | source | sid | 1.6.9-1 | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | forky | 1.6.9-1 | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | python-authlib | source | bookworm | 1.2.0-1+deb12u2 | not yet assigned | Not reported | Not reported |
| Pip | authlib | pip | Not reported | 1.6.9 | Not reported | Not reported | Not reported |
| Cpe | python-authlib | cpe | Not reported | 1.3.0-1ubuntu0.1~esm2 | Not reported | Not reported | Not reported |
| Cpe | python-authlib-doc | cpe | Not reported | 1.3.0-1ubuntu0.1~esm2 | Not reported | Not reported | Not reported |
| Cpe | python3-authlib | cpe | Not reported | 1.3.0-1ubuntu0.1~esm2 | Not reported | Not reported | Not reported |
| Cpe | authlib | cpe | Not reported | 1.6.9 | Not reported | NVD-CVE-2026-28498 | Not reported |
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [python3-authlib]Affected
Source package: [python-authlib]
Details (4)
1.2.0-1+deb12u1· all · bookwormAffected · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
1.2.0-1+deb12u1· all · bookwormAffected · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
- [python-authlib-doc]Affected
Source package: [python-authlib]
Details (4)
1.2.0-1+deb12u1· all · bookwormAffected · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
1.2.0-1+deb12u1· all · bookwormAffected · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
1.2.0-1+deb12u2· all · bookworm-securityFixed · Fixed:
1.2.0-1+deb12u2nvd · python-authlib · debian · bookworm; nvd · python-authlib · debian · 12
[Debian 13 (Trixie)]
- [python3-authlib]Affected
Source package: [python-authlib]
Details (2)
1.6.0-1+deb13u1· all · trixieAffected
nvd · python-authlib · debian · 13
1.6.0-1+deb13u1· all · trixieAffected
nvd · python-authlib · debian · 13
- [python-authlib-doc]Affected
Source package: [python-authlib]
Details (2)
1.6.0-1+deb13u1· all · trixieAffected
nvd · python-authlib · debian · 13
1.6.0-1+deb13u1· all · trixieAffected
nvd · python-authlib · debian · 13
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_20392-1.json]
- [https://github.com/advisories/GHSA-m344-f55w-2m6j]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-28498]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-28498]
- [https://security-tracker.debian.org/tracker/CVE-2026-28498]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-28498.json]
- [https://ubuntu.com/security/notices/USN-8557-1]
- [https://wid.cert-bund.de/.well-known/csaf/white/2026/wid-sec-w-2026-0935.json]
[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX] · [Ubuntu Security Notices (USN)]