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Vulnerabilities

Vulnerability · CVE-2026-27859

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

Published Mar 27, 2026 · catalog updated Jun 17, 2026 · A mail message containing

Check if you run it

No confirmed exploitation is on record for CVE-2026-27859. EPSS is 0.40%. Act only if a listed version of A mail message containing is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (A mail message containing).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Medium5.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.40%
Remediation
Advisory link
Affected products
cpe dovecot/dovecot · cpe open-xchange/dovecot

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

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

How to fix CVE-2026-27859

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-27859. EPSS is 0.40%. Act only if a listed version of A mail message containing is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption. EPSS 0.40%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

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. Mar 27, 2026 · NIST NVD

    Detected

    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.

  2. Jun 17, 2026 · NIST NVD

    Updated

    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.

Sources

  • CVE.orgVulnerability recordCVE-2026-27859

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27859

    30-day exploitation probability 0.4%

    first.org
  • NIST NVDVulnerability recordCVE-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 time. Use MTA capabilities to limit RFC 2231 MIME parameters in mail messages, or

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.