CVE-2026-33603
Fixed in a distro release EPSS <1%CVSS 6.8
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.
Products: Open-Xchange GmbH OX Dovecot Pro
Distro releases
| Release | Package | Fixed in |
|---|---|---|
| Alpine 3.23 | dovecot | 2.4.4-r0 |
| Alpine 3.24 | dovecot | 2.4.4-r0 |
| Debian 12 | dovecot | 1:2.3.19.1+dfsg1-2.1+deb12u6 |
| Debian 13 | dovecot | 1:2.4.1+dfsg1-6+deb13u6 |
| Debian 14 | dovecot | 1:2.4.4+dfsg1-1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Module for Server Applications 15 SP7 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 12 SP5-LTSS | dovecot22 | 2.2.31-19.37.2 |
| SUSE Linux Enterprise Server 15 SP4-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 15 SP5-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 15 SP6-LTSS | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server 16.0 | dovecot24 | 2.4.4-160000.1.1 |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | dovecot22 | 2.2.31-19.37.2 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | dovecot23 | 2.3.21.1-150200.76.1 |
| SUSE Linux Enterprise Server for SAP applications 16.0 | dovecot24 | 2.4.4-160000.1.1 |
| Ubuntu 16.04 LTS | dovecot | no fix |
| Ubuntu 18.04 LTS | dovecot | no fix |
| Ubuntu 20.04 LTS | dovecot | no fix |
| Ubuntu 22.04 LTS | dovecot | 1:2.3.16+dfsg1-3ubuntu2.9 |
| Ubuntu 24.04 LTS | dovecot | 1:2.3.21+dfsg1-2ubuntu6.5 |
| Ubuntu 25.10 | dovecot | 1:2.4.1+dfsg1-5ubuntu4.2 |
| Ubuntu 26.04 LTS | dovecot | 1:2.4.2+dfsg1-3ubuntu2.1 |
| Ubuntu Pro 14.04 LTS | dovecot | no fix |
| openSUSE Leap 16.0 | dovecot24 | 2.4.4-160000.1.1 |
| openSUSE Tumbleweed | dovecot24 | 2.4.4-1.1 |