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.
Fix
Patch, vendor advisory and mitigation references on NVD 1
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0002.json Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 5.3 · dovecot, open-xchangeNVD modified 2026-10-26 18:10
Affected (CPE criteria) 2
cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*cpe:2.3:a:open-xchange:dovecot:*:*:*:*:pro:*:*:*