VulnerabilityModified

CVE-2026-27858

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

HIGH 7.5EPSS 0.79%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.79%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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.

CVSS 3.1: 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.79% probability · 54th percentile
CISA KEV: Not listed
Weakness: CWE-400, CWE-770
Affected: dovecot/dovecot · open-xchange/dovecot
Source: security@open-xchange.com

References

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