CVE-2026-104056: authlib
CVSS: 9.8v3.1CriticalAwaiting analysis
AliasesUBUNTU-CVE-2026-104056DEBIAN-CVE-2026-104056
Published 01-10-2026Last modified 05-10-2026
Vulnerability summary
CVE-2026-104056 is a critical (CVSS 9.8) vulnerability in authlib. EPSS estimates a 0.17% chance of exploitation in the next 30 days, higher than 5.6% of scored vulnerabilities.
CVSS score
9.8/10
010
Critical · v3.1 (CVE.org)EPSS score
0.17%
0%100%
Low · Change unavailableKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 01-10-2026PublishedVulnerability first disclosed.
- 05-10-2026Last modifiedVulnerability information updated.
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.
CVSS metrics
4 scores · 4 sources · 1 versionCritical 9.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HSourcesAll 4 agree
- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.17%
Chance of exploitation in the next 30 days
Percentile
6%
Versus all other CVEs
30-day change
Change unavailable
Change unavailable
02-10-202620-10-2026
EPSS score0.17%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-345Insufficient Verification of Data AuthenticityThe product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.
- CWE-346Origin Validation ErrorThe product does not properly verify that the source of data or communication is valid.
- CWE-829Inclusion of Functionality from Untrusted Control SphereThe product imports, requires, or includes executable functionality (such as a library) from a source that is outside of the intended control sphere.
Affected systems
Authlib1 product
- authlib1.7.2
Debian1 product
- python-authlibAll versions (No fix recorded)
Ubuntu1 product
- python-authlibAll versions (No fix recorded)
3 vendors · 3 products
