CVE-2026-27860

medium

Published 2026-03-27 · Modified 2026-04-29

💬 Discuss on Community ✚ Propose mitigation

CVSS v3

5.3

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

CVSS v4 NEW

—

not yet in upstream

VIR risk

5.3

Description

If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. Do not clear out auth_username_chars, or install fixed version. No publicly available exploits are known.

Predictions

Exploit likelihood

63%

Patch ETA

—

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

OS	Version	Status	Fixed in
debian	bookworm	fixed	`0`
debian	bullseye	fixed	`0`
debian	forky	fixed	`1:2.4.3+dfsg1-1`
debian	sid	fixed	`1:2.4.3+dfsg1-1`
debian	trixie	fixed	`1:2.4.1+dfsg1-6+deb13u4`
sles		affected

Application impact

Vendor	Product	Versions	Fixed
dovecot	dovecot	`{"endExcluding":"2.4.3"}`	`2.4.3`
open-xchange	dovecot	`{"endExcluding":"3.1.4"}`	`3.1.4`

References

CWEs

CWE-90

Community-verified mitigations for this CVE will appear above when contributors publish them.

Verify integrity in audit chain (admin only). AS-IS.