high7.4
CVE-2026-27856
Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack.
Impact
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.
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Dovecot | Dovecot | before 2.4.3 |
| Open-Xchange | Dovecot | before 2.3.22.1 from 3.0.0 before 3.0.5 from 3.1.0 before 3.1.4 |
Weakness classification
References
- NVD record
- CVE.org record
- 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