| Name | CVE-2026-33603 |
| 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. |
| 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) |
| References | DSA-6313-1 |
| Debian Bugs | 1136444 |
The table below lists information on source packages.
| Source Package | Release | Version | Status |
|---|---|---|---|
| dovecot (PTS) | bullseye | 1:2.3.13+dfsg1-2+deb11u1 | vulnerable |
| bullseye (security) | 1:2.3.13+dfsg1-2+deb11u3 | vulnerable | |
| bookworm | 1:2.3.19.1+dfsg1-2.1+deb12u5 | vulnerable | |
| bookworm (security) | 1:2.3.19.1+dfsg1-2.1+deb12u6 | fixed | |
| trixie | 1:2.4.1+dfsg1-6+deb13u5 | vulnerable | |
| trixie (security) | 1:2.4.1+dfsg1-6+deb13u6 | fixed | |
| forky, sid | 1:2.4.4+dfsg1-1 | fixed |
The information below is based on the following data on fixed versions.
| Package | Type | Release | Fixed Version | Urgency | Origin | Debian Bugs |
|---|---|---|---|---|---|---|
| dovecot | source | bookworm | 1:2.3.19.1+dfsg1-2.1+deb12u6 | DSA-6313-1 | ||
| dovecot | source | trixie | 1:2.4.1+dfsg1-6+deb13u6 | DSA-6313-1 | ||
| dovecot | source | (unstable) | 1:2.4.4+dfsg1-1 | 1136444 |
https://www.openwall.com/lists/oss-security/2026/05/12/6
Fixed by: https://github.com/dovecot/core/commit/c1c53885bda550632b944dd305013cd010e0e058 (2.4.4)