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CVE-2026-27855

Published: Mar 27, 2026Updated: Apr 29, 2026 Sources: CVE List NVDCWE-294
6.8MEDIUM
NVD MITRE
EPSS Score
0.3%
Top 76.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
OpenVAS

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:RS:UC:HI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:RUser Interaction
Required
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-294

Affected Products

dovecot
oss-projectaka pigeonhole
dovecotOn-premWeb App
Communications / email-server-client
open-xchange
commercial·DEaka open-xchange gmbh, ox
dovecot
Communications
Open-Xchange GmbH
commercial·DEaka open-xchange
OX Dovecot Pro
Communications

Exploitability

Official Patch Available
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Attack Graph

Products CVE Techniques Tactics

Click technique nodes for MITRE ATT&CK details · drag to pan · Ctrl/⌘ + scroll to zoom, or go fullscreen.

MITRE ATT&CK

1 technique
Defense Evasion
View detailed technique mapping

References

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

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