6.8CVSSMEDIUM
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.
CVSS Vector Breakdown
Exploitability
AV:AAttack VectorAdjacent
AC:HAttack ComplexityHigh
PR:NPrivileges RequiredNone
UI:NUser InteractionNone
Scope
S:UScopeUnchanged
Impact
C:HConfidentialityHigh
I:HIntegrityHigh
A:NAvailabilityNone
Weaknesses
Affected Products
Exploitability
Official Patch Available
References
Timeline
Published
May 12, 2026
Last Updated
May 18, 2026
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