CVE-2026-27860

Public on 2026-03-27

Modified on 2026-07-17

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.

Severity

Low

See what this means

CVSS v3 Base Score

3.7

See breakdown

Affected Packages

Platform	Package	Release Date	Advisory	Status
Amazon Linux 2 - Core	dovecot			No Fix Planned
Amazon Linux 2023	dovecot			No Fix Planned

CVSS Scores

	Score Type	Score	Vector
Amazon Linux	CVSSv3	3.7	CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
NVD	CVSSv3	5.3	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

FAQs regarding Amazon Linux ALAS/CVE Severity Red Hat: CVE-2026-27860 Mitre: CVE-2026-27860