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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Open-Xchange | OX Dovecot Pro | ≤ 3.1.0, ≤ 2.4.0 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | dovecot | 1:2.4.3+dfsg1-1 | — |
| Debian 13 | dovecot | 1:2.4.1+dfsg1-6+deb13u4 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | dovecot | 1:2.4.1+dfsg1-5ubuntu4.1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | dovecot24 | 2.4.3-160000.1.1 | SUSE-SU-2026:21208-1 |
| SLES 16.0 | dovecot24 | 2.4.3-160000.1.1 | SUSE-SU-2026:21208-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dovecot24 | 2.4.3-1.1 | openSUSE-SU-2026:10442-1 |
| openSUSE Leap 16.0 | dovecot24 | 2.4.3-160000.1.1 | openSUSE-SU-2026:20554-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dovecot | 2.4.3-r0 | — |
| Alpine v3.23 | dovecot | 2.4.3-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | dovecot | No fix yet | — |
Advisories 4
- WID-SEC-2026-0891 Dovecot: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 16, 2026
- openSUSE-SU-2026:20554-1 Security update for dovecot24 SUSE / openSUSE Security Updates · Apr 22, 2026
- SUSE-SU-2026:21208-1 Security update for dovecot24 SUSE / openSUSE Security Updates · Apr 22, 2026
- openSUSE-SU-2026:10442-1 dovecot24-2.4.3-1.1 on GA media SUSE / openSUSE Security Updates · Mar 28, 2026