Vulnerability · Published Oct 1, 2026 · Assigned by certcc
CVE-2026-104056CVE-2026-104056
Critical 9.8
In plain English
A critical-severity insufficient verification of data authenticity in Authlib from Authlib. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities).
Official description
Authlib version 1.7.2 and below contains a vulnerability where discovery JSON metadata is cached without validation or issuer-origin binding. This allows a poisoned discovery response to replace all endpoint values with attacker-controlled values rather than endpoint URLs that share the origin of the configured server metadata URL.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | python-authlib | no fix listed | DEBIAN-CVE-2026-104056 |
| Debian:13 | python-authlib | no fix listed | DEBIAN-CVE-2026-104056 |
| Debian:14 | python-authlib | no fix listed | DEBIAN-CVE-2026-104056 |
| Ubuntu:26.10 | python-authlib | no fix listed | UBUNTU-CVE-2026-104056 |
Affected products (as reported)
Weakness: CWE-345, CWE-346, CWE-829 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H