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 confi...

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.

Metrics

CVSS 3.1

5.9/10

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

EPSS Probability

0.39%

31.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Dovecot	Dovecot	< 2.4.3
Open-Xchange	Dovecot	< 2.3.22.1
Open-Xchange	Dovecot	>= 3.0.0, < 3.0.5
Open-Xchange	Dovecot	>= 3.1.0, < 3.1.4

References

Timeline

Published: Mar 27, 2026
Last Modified: Jul 15, 2026
Status: Modified

Frequently Asked Questions

What is 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.

How severe is CVE-2026-27856?

CVE-2026-27856 has a CVSS score of 5.9/10 (MEDIUM severity). The EPSS model estimates a 0.39% probability of exploitation in the next 30 days.

How do I fix CVE-2026-27856?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

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