High7.5Red Hat & Ubuntu Linux
denial of service via crafted message before authentication
CVE-2026-27858 Published Mar 27, 2026
CVE-2026-27858
Affected products & platforms
Red Hat & Ubuntu LinuxUnclassified
Summary
denial of service via crafted message before authentication. Red Hat rates this important (CVSS 7.5). Weakness: CWE-770. Affected package(s): dovecot. Resolved in Red Hat advisory RHSA-2026:26564 — update the affected packages (`sudo dnf update`).
Affected versions
- dovecot-1:2.2.36-8.el7_9.1
- dovecot-1:2.3.16-8.el9_2.2
- dovecot-1:2.3.16-3.el9_0.1
- dovecot-1:2.3.16-18.el9_8
- dovecot-1:2.3.21-19.el10_2
- dovecot-1:2.3.16-3.el8_8.1
- dovecot-1:2.3.8-9.el8_4.1
- dovecot-1:2.3.16-15.el9_6.1
- dovecot-1:2.3.21-16.el10_0.1
- dovecot-1:2.3.16-15.el9_7.1
- dovecot-1:2.3.16-11.el9_4.2
- dovecot-1:2.3.21-16.el10_1.1
Official advisory · high-confidence parse· fetched 1 day ago·verify at source
Fixed versions
- RHSA-2026:26564
Official advisory · high-confidence parse· fetched 1 day ago·verify at source
Mitigation checklist
Recommended fix / mitigation
- Update the affected package(s) to the fixed version shipped in RHSA-2026:26564 (`sudo dnf update` / `yum update`).
Official advisory · high-confidence parse· fetched 1 day ago·verify at source
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