VulnerabilityAnalyzed

CVE-2026-27859

A mail message containing excessive amount of RFC 2231 MIME parameters causes LMTP to use too much CPU.

MEDIUM 5.3EPSS 0.37%

Does this matter?

Lower severity and a low EPSS score (0.37%). Track it; it rarely justifies an emergency change on its own.

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 3.1: 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
EPSS: 0.37% probability · 31th percentile
CISA KEV: Not listed
Weakness: CWE-400
Affected: dovecot/dovecot · open-xchange/dovecot
Source: security@open-xchange.com

References

https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.jsonVendor Advisory

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.