What is CVE-2026-27860?

CVE-2026-27860 is a low-severity vulnerability in Dovecot, classified under LDAP Injection. CVSS score: 3.7/10. Published 2026-03-27.

How severe is CVE-2026-27860?

Low severity. CVSS v3 base score is 3.7 out of 10.

LDAP Injection in Dovecot

CVE-2026-27860

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.

Published 2026-03-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 3.7 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N.

EPSS exploit prediction

EPSS: 0.003 (26.6th percentile), scored 2026-10-23.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 27th percentile — 26.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.003 · change: +0.001

Affected products

Dovecot
Open-Xchange Dovecot
Open-Xchange Gmbh Ox Dovecot Pro — versions 0

Weakness classification (CWE)

CWE-90 — LDAP Injection

References

documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2… (vendor-advisory, Vendor Advisory)

Frequently asked questions

What is CVE-2026-27860?: CVE-2026-27860 is a low-severity vulnerability in Dovecot, classified under LDAP Injection. CVSS score: 3.7/10. Published 2026-03-27.
How severe is CVE-2026-27860?: Low severity. CVSS v3 base score is 3.7 out of 10.