Description
Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding. This requires that the attacker is able to position itself between Dovecot and the client connection. If successful, the attacker can eavesdrop communications between Dovecot and client as MITM proxy. 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 | 1:2.4.4+dfsg1-1 | — |
| Debian 13 | dovecot | 1:2.4.1+dfsg1-6+deb13u6 | — |
| Debian 12 | dovecot | 1:2.3.19.1+dfsg1-2.1+deb12u6 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.04 LTS | dovecot | 1:2.4.2+dfsg1-3ubuntu2.1 | — |
| Ubuntu 25.10 | dovecot | 1:2.4.1+dfsg1-5ubuntu4.2 | — |
| Ubuntu 24.04 LTS | dovecot | 1:2.3.21+dfsg1-2ubuntu6.5 | — |
| Ubuntu 22.04 LTS | dovecot | 1:2.3.16+dfsg1-3ubuntu2.9 | — |
| Ubuntu 20.04 LTS | dovecot | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 18.04 LTS | dovecot | No fix yet | — |
| Ubuntu 16.04 LTS | dovecot | No fix yet | — |
| Ubuntu Pro 14.04 LTS | dovecot | No fix yet | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP7 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 15 SP6 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 12 SP5 | dovecot22 | 2.2.31-19.37.2 | SUSE-SU-2026:2645-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 16.0 | dovecot24 | 2.4.4-160000.1.1 | SUSE-SU-2026:22185-1 |
| SLES for SAP 15 SP6 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES for SAP 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES for SAP 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLES 16.0 | dovecot24 | 2.4.4-160000.1.1 | SUSE-SU-2026:22185-1 |
| SLE HPC 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
| SLE HPC 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 | SUSE-SU-2026:4139-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | dovecot24 | 2.4.4-1.1 | openSUSE-SU-2026:10766-1 |
| openSUSE Leap 16.0 | dovecot24 | 2.4.4-160000.1.1 | openSUSE-SU-2026:21109-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | dovecot | 2.4.4-r0 | — |
| Alpine v3.23 | dovecot | 2.4.4-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | dovecot | No fix yet | — |
Advisories 6
- SUSE-SU-2026:4139-1 Security update for dovecot23 SUSE / openSUSE Security Updates · Sep 28, 2026
- WID-SEC-2026-1510 OX Dovecot Pro: Mehrere Schwachstellen BSI CERT-Bund (WID) · Sep 21, 2026
- openSUSE-SU-2026:21109-1 Security update for dovecot24 SUSE / openSUSE Security Updates · Jun 30, 2026
- SUSE-SU-2026:2645-1 Security update for dovecot22 SUSE / openSUSE Security Updates · Jun 27, 2026
- SUSE-SU-2026:22185-1 Security update for dovecot24 SUSE / openSUSE Security Updates · Jun 24, 2026
- openSUSE-SU-2026:10766-1 dovecot24-2.4.4-1.1 on GA media SUSE / openSUSE Security Updates · May 14, 2026