Medium severity6.8NVD Advisory· Published Mar 27, 2026· Updated Apr 29, 2026
CVE-2026-27855
CVE-2026-27855
Description
Dovecot OTP authentication is vulnerable to replay attack under specific conditions. If auth cache is enabled, and username is altered in passdb, then OTP credentials can be cached so that same OTP reply is valid. An attacker able to observe an OTP exchange is able to log in as the user. If authentication happens over unsecure connection, switch to SCRAM protocol. Alternatively ensure the communcations are secured, and if possible switch to OAUTH2 or SCRAM. No publicly available exploits are known.
Affected products
7cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*+ 1 more
- cpe:2.3:a:dovecot:dovecot:*:*:*:*:*:*:*:*range: <2.4.3
- (no CPE)
- osv-coords4 versionspkg:rpm/opensuse/dovecot24&distro=openSUSE%20Leap%2016.0pkg:rpm/opensuse/dovecot24&distro=openSUSE%20Tumbleweedpkg:rpm/suse/dovecot24&distro=SUSE%20Linux%20Enterprise%20Server%2016.0pkg:rpm/suse/dovecot24&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20applications%2016.0
< 2.4.3-160000.1.1+ 3 more
- (no CPE)range: < 2.4.3-160000.1.1
- (no CPE)range: < 2.4.3-1.1
- (no CPE)range: < 2.4.3-160000.1.1
- (no CPE)range: < 2.4.3-160000.1.1
Patches
Vulnerability mechanics
References
1News mentions
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