CVE-2026-27856Doveadm credentials are verified using direct comparison which is susceptible to timing oracle attack.
Updated under an hour ago ()
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It affects dovecot and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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
- 5.9 MEDIUM (v3.1, NVD)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-287, CWE-208
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Modified
- Record last updated
- Jul 15, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
dovecot dovecot dovecot:dovecot | before 2.4.3 | NVD |
open-xchange dovecot open-xchange:dovecot | before 2.3.22.1; from 3.0.0 before 3.0.5; from 3.1.0 before 3.1.4 | NVD |
References
- https://documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.jsonvendor-advisory
- 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
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.