CVE-2026-27856

Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack. An attacker can use this to determine the configured credentials. Figuring out the credential will lead into full access to the affected component. Limit access to the doveadm http service port, install fixed version. No publicly available exploits are known.

CVSS 3.1

5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

0.4% chance of exploitation in the next 30 days; higher than 33% of CVEs (scores of 2026-10-26)

CWEs

CWE-287, CWE-208

Published

2026-03-27

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• dovecot:dovecot
• open-xchange:dovecot

References

• https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json
• https://access.redhat.com/errata/RHSA-2026:26564
• https://access.redhat.com/security/cve/CVE-2026-27856
• https://bugzilla.redhat.com/show_bug.cgi?id=2452171
• https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27856.json

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