Is CVE-2026-27856 in the CISA KEV catalog?

No. CVE-2026-27856 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2026-27856?

CVE-2026-27856 has a CVSS v3 base score of 7.4 (HIGH).

What is the EPSS score for CVE-2026-27856?

CVE-2026-27856 has an EPSS score of 0.29% (21th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2026-27856

HIGH

7.4

CVSS v3

NVD

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.

CWE-287Improper Authentication

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityNone

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

Exploit Intelligence

0.29%probability of exploitation in 30 days

21stpercentile

Low risk: more likely to be exploited than 21% of all known CVEs.

References

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

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-29.