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Fencer Vulns
high 7.7

CVE-2026-24031 json

Dovecot SQL based authentication can be bypassed when auth_username_chars is cleared by admin.

published 2026-03-27 7 mo ago modified 2026-10-26 13 d ago also EUVD-2026-16561

cvss
7.7
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 34%
public exploits
0
none known

Summary

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.

Patch / fix

  • dovecot dovecot 2.4.3, 3.1.4
  • open-xchange dovecot 2.4.3, 3.1.4
  • dovecot Debian 13 1:2.4.1+dfsg1-6+deb13u4
  • dovecot Debian 14 1:2.4.3+dfsg1-1

debian advisories DEBIAN-CVE-2026-24031

  • dovecot Ubuntu 25.10 1:2.4.1+dfsg1-5ubuntu4.1

ubuntu advisories UBUNTU-CVE-2026-24031

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • dovecot24 SLES for SAP applications 16.0, SLES 16.0 2.4.3-160000.1.1

suse advisories SUSE-SU-2026:21208-1

  • dovecot24 openSUSE Leap 16.0 2.4.3-160000.1.1
  • dovecot24 openSUSE Tumbleweed 2.4.3-1.1

opensuse advisories openSUSE-SU-2026:20554-1openSUSE-SU-2026:10442-1

  • dovecot Alpine 3.24, Alpine 3.23 2.4.3-r0

alpine advisories ALPINE-CVE-2026-24031

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-24031 updated cvss 7.7

dovecot: Dovecot: Authentication bypass and user enumeration due to cleared auth_username_chars configuration

  • Red Hat Enterprise Linux 6 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole
    affected: no fix planned “Will not fix”
  • Red Hat Enterprise Linux 7 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 8 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 9 dovecot, dovecot-mysql, dovecot-pgsql, dovecot-pigeonhole Red Hat Enterprise Linux 10 dovecot
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.40% chance of exploitation in the next 30 days, higher than 34% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 7.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
CISA ADP 3.1 7.7 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L
NVD 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:N

Affected products

  • Open-Xchange GmbH OX Dovecot Pro
  • Red Hat Red Hat Enterprise Linux 10
  • Red Hat Red Hat Enterprise Linux 6
  • Red Hat Red Hat Enterprise Linux 7
  • Red Hat Red Hat Enterprise Linux 8
  • Red Hat Red Hat Enterprise Linux 9

Classification

Weakness
  • CWE-89 Improper Neutralization of Special Elements used in an SQL Command

References

Sources

Fencer Vulns 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.