VulnerabilityAnalyzed
CVE-2026-33603
Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding.
MEDIUM 5.3EPSS 0.21%
Does this matter?
Lower severity and a low EPSS score (0.21%). Track it; it rarely justifies an emergency change on its own.
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 3.1
- 5.3 MEDIUMCVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- EPSS
- 0.21% probability · 12th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-99
- Affected
- dovecot/dovecot · open-xchange/dovecot
- Source
- security@open-xchange.com
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.