Authlib: Prior to 1.9.0, the default RFC 7523 JWTBearerGrant.get_audiences() returns an empty list, causing
Affects authlibSource GCVE Database
Not known to be exploited · CVSS 6.8 Medium : upgrade to 1.9.0 when convenient.
Data as of 30 Oct 2026, 11:52 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 3.1 | 6.8 |
|---|
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.9.0
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 22 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade authlib to 1.9.0.
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
PyPIauthlibpkg:pypi/authlibOther threats | Affected
| Fixed in
|
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AI-suggested
Upgrade Authlib to version 1.9.0 or later, where this issue is fixed. Alternatively, ensure that the get_audiences() method is overridden to return the server's valid audience identifiers to prevent misuse. Since a patch is available and the vulnerability is fixed in 1.9.0, applying the official update is the recommended remediation.
Description
Authlib versions prior to 1.9.0 have a vulnerability in the default implementation of JWTBearerGrant.get_audiences() where it returns an empty list. This causes the verify_claims() method to only check for the presence of an aud claim without verifying it matches the current authorization server. As a result, an attacker with a valid assertion for another service sharing the signing key can obtain an access token from the vulnerable server. This issue is fixed in Authlib version 1.9.0.
References
- github.com/authlib/authlib/releases/tag/v1.9.0 (opens in a new tab)
- github.com/authlib/authlib/commit/e3bd41cb29dcfee434453b135ffb487884baeedf (opens in a new tab)
- github.com/authlib/authlib/pull/945 (opens in a new tab)
- github.com/authlib/authlib/security/advisories/GHSA-fch4-3c6x-j4gc (opens in a new tab)