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MEDIUM · 5.3

CVE-2026-27859

A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU t...

Vulnerability Description

A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU time. Use MTA capabilities to limit RFC 2231 MIME parameters in mail messages, or upgrade to fixed version where the processing is limited. No publicly available exploits are known.

CVSS Score

5.3

MEDIUM

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
LOW

Affected Products

VendorProductVersions
DovecotDovecot< 2.4.3
Open-XchangeDovecot< 3.0.5

Related Weaknesses (CWE)

CWE-400

References

FAQ

What is CVE-2026-27859?

CVE-2026-27859 is a vulnerability with a CVSS score of 5.3 (MEDIUM). A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU. A suitably formatted mail message causes mail delivery process to consume large amounts of CPU t...

How severe is CVE-2026-27859?

CVE-2026-27859 has been rated MEDIUM with a CVSS base score of 5.3/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-27859?

Check the references section above for vendor advisories and patch information. Affected products include: Dovecot Dovecot, Open-Xchange Dovecot.