# CVE-2025-66621: Apache James: SASL OAUTHBEARER do not validate aud in JWT payload if misconfigred

Status: published. Published: 2026-11-06. Updated: 2026-11-06.

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.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- Apache Software Foundation / Apache James: ≥ 3.9.0; < 3.9.1 (affected, semver). Source: CNA: apache

## Severity and prioritization

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-345

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://lists.apache.org/thread.html/xz1g0blzcbxod69oktyq84h7t06xzov6 (CNA: apache; vendor-advisory)

## Provenance

- CNA: apache: https://www.cve.org/CVERecord?id=CVE-2025-66621; retrieved 2026-11-06; source updated 2026-11-06

Revision: e81c08ee5b78d140dba56df96a26541ae1a46ca1f2bd938272f13901c892547a

Canonical: https://y2.dev/cve/CVE-2025-66621

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