CVE-2026-33604

Summary

CVECVE-2026-33604
StatePUBLISHED
AssignerOX
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 12:16:27 UTC
Updated2026-08-28 20:17:25 UTC
DescriptionAn attacker that can get Dovecot to relay a message, for example through Sieve redirect or submission relay, can use a crafted line ending in the message body to bypass the outbound protection that prevents message content from being interpreted as SMTP commands. A downstream mail server that hasn't yet fixed the SMTP smuggling vulnerability can be tricked into treating part of the message body as new SMTP commands, allowing injection of spoofed email. This is the same vulnerability class as CVE-2023-51764 and CVE-2023-51766. Where you control the receiving mail servers, ensure they reject bare carriage returns in message data. Update to non-vulnerable version. No publicly available exploits are known.

Risk And Classification

Primary CVSS: v3.1 5.9 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Problem Types: CWE-655 | CWE-655 Insufficient Psychological Acceptability


VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N
3.1CNACVSS5.9MEDIUMCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Open-Xchange GmbH OX Dovecot Pro affected 2.3.0 2.3.22.2 semver Not specified
CNA Open-Xchange GmbH OX Dovecot Pro affected 3.0.0 3.0.7 semver Not specified
CNA Open-Xchange GmbH OX Dovecot Pro affected 3.1.0 3.1.6 semver Not specified
CNA Open-Xchange GmbH OX Dovecot CE affected 2.3.0 2.4.5 semver Not specified

References

ReferenceSourceLinkTags
documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0003.json [email protected] documentation.open-xchange.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

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