CVE-2026-27858
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.8%
exploitation probability
0.8%top 47% of all CVEs
observed exploitation
nono source reports it
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/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products
Open-Xchange GmbH · OX Dovecot ProReferences
https://access.redhat.com/errata/RHSA-2026:13498https://access.redhat.com/errata/RHSA-2026:13830https://access.redhat.com/errata/RHSA-2026:13857https://access.redhat.com/errata/RHSA-2026:17602https://access.redhat.com/errata/RHSA-2026:17625https://access.redhat.com/errata/RHSA-2026:17626https://access.redhat.com/errata/RHSA-2026:17628https://access.redhat.com/errata/RHSA-2026:17630https://access.redhat.com/errata/RHSA-2026:18053https://access.redhat.com/errata/RHSA-2026:19149https://access.redhat.com/errata/RHSA-2026:19364https://access.redhat.com/errata/RHSA-2026:19453