| Name | CVE-2026-27860 |
| 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. |
| Source | CVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more) |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| dovecot (PTS) | bullseye | 1:2.3.13+dfsg1-2+deb11u1 | fixed |
| bullseye (security) | 1:2.3.13+dfsg1-2+deb11u2 | fixed | |
| bookworm | 1:2.3.19.1+dfsg1-2.1+deb12u1 | fixed | |
| bookworm (security) | 1:2.3.19.1+dfsg1-2.1+deb12u3 | fixed | |
| trixie | 1:2.4.1+dfsg1-6+deb13u3 | vulnerable | |
| trixie (security) | 1:2.4.1+dfsg1-6+deb13u4 | fixed | |
| forky, sid | 1:2.4.3+dfsg1-2 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| dovecot | source | bullseye | (not affected) | |||
| dovecot | source | bookworm | (not affected) | |||
| dovecot | source | trixie | 1:2.4.1+dfsg1-6+deb13u4 | |||
| dovecot | source | (unstable) | 1:2.4.3+dfsg1-1 |
[bookworm] - dovecot <not-affected> (Specific to 2.4.x)
[bullseye] - dovecot <not-affected> (Specific to 2.4.x)
https://dovecot.org/mailman3/archives/list/dovecot-news@dovecot.org/thread/IKIHZX77IPTGSP5WBIPJUOFBUQFKVPE7/
https://documentation.open-xchange.com/dovecot/security/advisories/html/2026/oxdc-adv-2026-0001.html#cve-2026-27860-v2-4-v3-1-regression-auth-ldap-is-not-escaping-usernames
Fixed by: https://github.com/dovecot/core/commit/e2d8ef1ee04662e391e06ae76da1e7216c3a1fd3 (2.4.3)
Fixed by: https://github.com/dovecot/core/commit/6a8f2daf15727a36488252efc184dacaa7652cd2 (2.4.3)
Fixed by: https://github.com/dovecot/core/commit/34fbd3956db7f0ab1aefccb7750b4ec984681fa8 (2.4.3)
Fixed by: https://github.com/dovecot/core/commit/0e1f5abbbb27d7f8a485cd1c6a5673be995025a4 (2.4.3)
Fixed by: https://github.com/dovecot/core/commit/74a6f1612e7732026e69e8d8489291842df68589 (2.4.3)
Fixed by: https://github.com/dovecot/core/commit/25c34e50848155786d9a00eef6c310502f94e70f (2.4.3)
Fixed by: https://github.com/dovecot/core/commit/4049b0a8d5b6ca5c2cbcaadb9b5e81c3cce25044 (2.4.3)