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Vulnerabilities

Vulnerability · CVE-2026-27858

Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory.

Published Mar 27, 2026 · catalog updated Jul 15, 2026 · Attacker can send a

Check if you run it

No confirmed exploitation is on record for CVE-2026-27858. EPSS is 1.04%. Act only if a listed version of Attacker can send a is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (Attacker can send a).
  • 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
High7.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.04%
Remediation
Advisory link
Affected products
cpe dovecot/dovecot · cpe open-xchange/dovecot

Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. 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-2026-27858

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-2026-27858. EPSS is 1.04%. Act only if a listed version of Attacker can send a 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; CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 1.04%. 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

    Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits are known.

  2. Jul 15, 2026 · NIST NVD

    Updated

    Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed version. No publicly available exploits are known.

Sources

  • CVE.orgVulnerability recordCVE-2026-27858

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-27858

    30-day exploitation probability 1.0%

    first.org
  • NIST NVDVulnerability recordCVE-2026-27858

    Attacker can send a specifically crafted message before authentication that causes managesieve to allocate large amount of memory. Attacker can force managesieve-login to be unavailable by repeatedly crashing the process. Protect access to managesieve protocol, or install fixed

    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.