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.

How to fix

Remediation Available
dovecotDebian
Fixed in:1:2.3.13+dfsg1-2+deb11u3CVE-2026-27856
Fixed in:1:2.3.19.1+dfsg1-2.1+deb12u2CVE-2026-27856
Fixed in:1:2.4.1+dfsg1-6+deb13u4CVE-2026-27856
Fixed in:1:2.4.3+dfsg1-1CVE-2026-27856
dovecotRed Hat / RHEL
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppcRHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.s390RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecotRocky
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.s390RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppcRHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-debuginfoRed Hat / RHEL
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppcRHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.s390RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-debuginfoRocky
Fixed in:1:2.2.36-8.el7_9.1.ppcRHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.s390RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-develRed Hat / RHEL
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
dovecot-develRocky
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-mysqlRed Hat / RHEL
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-mysqlRocky
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-pgsqlRocky
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-pgsqlRed Hat / RHEL
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecot-pigeonholeRed Hat / RHEL
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
dovecot-pigeonholeRocky
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1.ppc64RHSA-2026:26564
Fixed in:1:2.2.36-8.el7_9.1RHSA-2026:26564
dovecotUbuntu
Fixed in:1:2.3.16+dfsg1-3ubuntu2.7USN-8136-1
Fixed in:1:2.3.21+dfsg1-2ubuntu6.3USN-8136-1
Fixed in:1:2.4.1+dfsg1-5ubuntu4.1USN-8136-1
dovecot-coreUbuntu
Fixed in:1:2.3.16+dfsg1-3ubuntu2.7USN-8136-1
Fixed in:1:2.3.21+dfsg1-2ubuntu6.3USN-8136-1
Fixed in:1:2.4.1+dfsg1-5ubuntu4.1USN-8136-1

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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

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

0.39%probability of exploitation in 30 days
32ndpercentile

Low risk: more likely to be exploited than 32% of all known CVEs.

References

Related Vulnerabilities

Other CWE-287 (Improper Authentication) vulnerabilities, ordered by exploit likelihood. View all

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CVE-2023-35082Critical9.8100%KEV + RansomFix
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CVE-2017-7921Critical9.8100%KEV-
CVE-2024-7593Critical9.8100%KEV-
CVE-2023-46805High8.2100%KEV + Ransom-
CVE-2022-40684Critical9.8100%KEV + RansomFix
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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 2026-07-15.