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Fencer Intel
medium —

CVE-2025-66621 json

Apache James: SASL OAUTHBEARER do not validate aud in JWT payload if misconfigred

published 3d ago modified 6h ago also EUVD-2025-211271

cvss
—
not scored
cisa kev
Not listed
not in CISA's catalog
epss
0.1%
EPSS 0.1% chance of exploitation in 30 days, percentile 3%
public exploits
0
none known

Summary

Apache James SASL OAuthBearer/XOAUTH2 prior versions 3.9.1 fails to validate correctly AUD claim of JWT payloads when introspection is not configured.

This allows an attacker with valid credentials to access the mail server even if they are not authorized to do so.

We recommend users to upgrade to non vulnerable version that forces explicit configuration of aud claims and forces introspection.

Patch / fix

  • Apache Software Foundation Apache James 3.9.1

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Exploit prediction

0.14% chance of exploitation in the next 30 days, higher than 3% of all scored CVEs (FIRST EPSS, 2026-11-09).

Affected products

  • Apache Software Foundation Apache James

Classification

Weakness
  • CWE-345 Insufficient Verification of Data Authenticity

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.