What is CVE-2023-27582?

CVE-2023-27582 is a critical-severity vulnerability in Foxcpp Maddy, classified under Improper Authentication. CVSS score: 9.1/10. Published 2023-03-13.

How severe is CVE-2023-27582?

Critical severity. CVSS v3 base score is 9.1 out of 10.

Auth bypass in Foxcpp Maddy

CVE-2023-27582

maddy is a composable, all-in-one mail server. Starting with version 0.2.0 and prior to version 0.6.3, maddy allows a full authentication bypass if SASL authorization username is specified when using the PLAIN authentication mechanisms. Instead of validating the specified username, it is accepted as is after checking the credentials for the authentication username. maddy 0.6.3 includes the fix for the bug. There are no known workarounds.

Vulnerability class: Broken Authentication

Published 2023-03-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 9.1 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N.

EPSS exploit prediction

EPSS: 0.010 (61.9th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 62nd percentile — 61.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.010 · newest: 0.010 · change: 0.000

Affected products

Foxcpp Maddy — versions >= 0.2.0 0.6.3
Maddy Project

Weakness classification (CWE)

References

github.com/foxcpp/maddy/security/advisories/GHSA-4g76-w3xw-2x6w (Patch, Vendor Advisory)
github.com/foxcpp/maddy/commit/55a91a37b71210f34f98f4d327c30308fe24399a (Patch)
github.com/foxcpp/maddy/commit/9f58cb64b39cdc01928ec463bdb198c4c2313a9c (Patch)
github.com/foxcpp/maddy/releases/tag/v0.6.3 (Release Notes)

Frequently asked questions

What is CVE-2023-27582?: CVE-2023-27582 is a critical-severity vulnerability in Foxcpp Maddy, classified under Improper Authentication. CVSS score: 9.1/10. Published 2023-03-13.
How severe is CVE-2023-27582?: Critical severity. CVSS v3 base score is 9.1 out of 10.