CVE-2026-27860

Name: CVE-2026-27860
Creator: NVD / NIST
Published: 2026-03-27T09:16:20.383+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 5.3/10EPSS 0.29%

Last modified Jun 17, 2026

CVE-2026-27860 is a medium-severity vulnerability rated 5.3/10 on the CVSS scale. If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. EPSS estimates a 0.29% chance of exploitation in the next 30 days.

Description

If auth_username_chars is empty, it is possible to inject arbitrary LDAP filter to Dovecot's LDAP authentication. This leads to potentially bypassing restrictions and allows probing of LDAP structure. Do not clear out auth_username_chars, or install fixed version. No publicly available exploits are known.

Metrics

CVSS 3.1

5.3/10

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

EPSS Probability

0.29%

20.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-90

Affected Software

Vendor	Product	Versions
Dovecot	Dovecot	< 2.4.3
Open-Xchange	Dovecot	< 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-2026-27860?

How severe is CVE-2026-27860?

CVE-2026-27860 has a CVSS score of 5.3/10 (MEDIUM severity). The EPSS model estimates a 0.29% probability of exploitation in the next 30 days.

How do I fix CVE-2026-27860?

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-2026-27860?

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

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Source: NVD / NIST