CVE-2026-24031

Severity: high (CVSS 8.2 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-03-27 · updated 2026-10-26
Weakness: CWE-89

Description

Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin. This vulnerability allows bypassing authentication for any user and user enumeration. Do not clear auth_username_chars. If this is not possible, install latest fixed version. No publicly available exploits are known.

Affected products

dovecot: before 2.4.3 — fixed in 2.4.3
Open-Xchange Dovecot: before 3.1.4 — fixed in 3.1.4

How to fix

Upgrade to a fixed version: dovecot 2.4.3; Open-Xchange Dovecot 3.1.4. Check the vendor advisory for mitigations.

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json
https://access.redhat.com/security/cve/CVE-2026-24031
https://bugzilla.redhat.com/show_bug.cgi?id=2452181
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-24031.json

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