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HIGH · 7.4

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 wil...

Vulnerability 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.

CVSS Score

7.4

HIGH

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Attack Vector
NETWORK
Attack Complexity
HIGH
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
NONE

Affected Products

VendorProductVersions
DovecotDovecot< 2.4.3
Open-XchangeDovecot< 2.3.22.1

Related Weaknesses (CWE)

CWE-287

References

FAQ

What is CVE-2026-27856?

CVE-2026-27856 is a vulnerability with a CVSS score of 7.4 (HIGH). 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 wil...

How severe is CVE-2026-27856?

CVE-2026-27856 has been rated HIGH with a CVSS base score of 7.4/10. Review the CVSS metrics above for detailed severity breakdown.

Is there a patch for CVE-2026-27856?

Check the references section above for vendor advisories and patch information. Affected products include: Dovecot Dovecot, Open-Xchange Dovecot.