High7.5Red Hat & Ubuntu Linux
RRSIG rdlen underflow leading to heap OOB read
CVE-2026-4891 Published May 9, 2026
CVE-2026-4891
Affected products & platforms
Red Hat & Ubuntu LinuxUnclassified
Summary
RRSIG rdlen underflow leading to heap OOB read. Red Hat rates this important (CVSS 7.5). Weakness: CWE-125. Affected package(s): dnsmasq. Resolved in Red Hat advisory RHSA-2026:20589 — update the affected packages (`sudo dnf update`).
Affected versions
- dnsmasq-0:2.85-17.el9_6.1
- dnsmasq-0:2.90-7.el10_2
- dnsmasq-0:2.85-18.el9_8.1
- dnsmasq-0:2.79-36.el8_10
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
- RHSA-2026:20589
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
Recommended fix / mitigation
- Update the affected package(s) to the fixed version shipped in RHSA-2026:20589 (`sudo dnf update` / `yum update`).
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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