CVE-2026-27858

Name: CVE-2026-27858
Creator: NVD / NIST
Published: 2026-03-27T09:16:20.073+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.46%

Last modified Jun 17, 2026

CVE-2026-27858 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. 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. EPSS estimates a 0.46% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.46%

36.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-400

Affected Software

Vendor	Product	Versions
Dovecot	Dovecot	< 2.4.3
Open-Xchange	Dovecot	< 2.3.22.1
Open-Xchange	Dovecot	>= 3.0.0, < 3.0.5
Open-Xchange	Dovecot	>= 3.1.0, < 3.1.4

References

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

Timeline

Published: Mar 27, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-27858?

How severe is CVE-2026-27858?

CVE-2026-27858 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.46% probability of exploitation in the next 30 days.

How do I fix CVE-2026-27858?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-27858?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST