Attacker can use a specially crafted base64 exchange between Dovecot and Client to fake SCRAM TLS channel binding.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

1. May 12, 2026 · NIST NVD

   Detected

   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.

2. Jun 17, 2026 · NIST NVD

   Updated

   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

• cpe dovecot/dovecotversion unspecified
• cpe open-xchange/dovecotversion unspecified

Sources

• CVE.orgVulnerability recordCVE-2026-33603

  Official CVE identifier

  cve.org
• NIST NVDVulnerability recordCVE-2026-33603

  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 betwee

  nvd.nist.gov

References

• Vendor Advisory · documentation.open-xchange.com