CVE-2026-27856
Summary
| CVE | CVE-2026-27856 |
|---|---|
| State | PUBLISHED |
| Assigner | OX |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-27 09:16:19 UTC |
| Updated | 2026-06-30 03:17:58 UTC |
| Description | 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. |
Risk And Classification
Primary CVSS: v3.1 5.9 MEDIUM from [email protected]
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
EPSS: 0.000390000 probability, percentile 0.117840000 (date 2026-04-06)
Problem Types: CWE-287 | NVD-CWE-Other | CWE-208 | CWE-287 Improper Authentication | CWE-208 Observable Timing Discrepancy
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 5.9 | MEDIUM | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N |
| 3.1 | ADP | CVSS | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | [email protected] | Secondary | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
| 3.1 | CNA | CVSS | 7.4 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
HighPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
HighIntegrity
NoneAvailability
NoneCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Dovecot | Dovecot | All | All | All | All |
| Application | Open-xchange | Dovecot | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Open-Xchange GmbH | OX Dovecot Pro | affected 2.3.0 semver | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux Server V. 7 ELS | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux Server Optional V. 7 ELS | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 6 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 10 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 8 | Not specified | Not specified |
| ADP | Red Hat | Red Hat Enterprise Linux 9 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| documentation.open-xchange.com/dovecot/security/advisories/csaf/2026/oxdc-adv-2026-0001.json | [email protected] | documentation.open-xchange.com | Vendor Advisory |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27856.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:26564 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-27856 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-03-27T09:01:28.297Z | Reported to Red Hat. |
| ADP | 2026-03-27T08:10:19.537Z | Made public. |
Solutions
ADP: RHSA-2026:26564: Red Hat Enterprise Linux Server (v. 7 ELS), Red Hat Enterprise Linux Server Optional (v. 7 ELS)
There are currently no legacy QID mappings associated with this CVE.