CVE-2026-33603

Summary

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 Software

VendorProductVersion RangeStatus
Open-Xchange GmbHOX Dovecot Pro0 <= 3.1.0affected
Open-Xchange GmbHOX Dovecot Pro0 <= 2.4.0affected

Weaknesses

  • CWE-99: Improper Control of Resource Identifiers ('Resource Injection')

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: total

References