Vulnerability in Apache Pony Mail

CVE-2026-41873

** UNSUPPORTED WHEN ASSIGNED ** Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Pony Mail leading to admin account takeover. This issue affects all versions of the Lua implementation of Pony Mail. There is a Python implementation under development under the name "Pony Mail Foal" that is not affected by this issue, but hasn't been released yet. As the Lua implementation of this project is retired, we do not plan to release a version that fixes this issue. Users are recommended to find an alternative or restrict access to the instance to trusted users. NOTE: This vulnerability only affects products that are no longer supported by the maintainer.

Vulnerability class: HTTP Request Smuggling

EPSS: 0.004 (37.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-41873?
CVE-2026-41873 is a critical-severity vulnerability in Apache Pony Mail, classified under Inconsistent Interpretation of HTTP Requests (HTTP Request/Response Smuggling). CVSS score: 9.8/10. Published 2026-04-28.
How severe is CVE-2026-41873?
Critical severity. CVSS v3 base score is 9.8 out of 10.