High [CVE-2026-4891] RRSIG rdlen underflow leading to heap OOB read
This high-severity Red Hat Linux advisory covers CVE-2026-4891 affecting Red Hat Enterprise Linux 10, Red Hat Enterprise Linux 8, Red Hat Enterprise Linux 9.6 Extended Update Support.
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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 products named by the advisory: Red Hat Enterprise Linux 10; Red Hat Enterprise Linux 8; Red Hat Enterprise Linux 9.6 Extended Update Support; Red Hat Enterprise Linux 6; and 2 more.
- 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 months ago·verify at source
- RHSA-2026:20589
Official advisory · high-confidence parse· fetched 2 months ago·verify at source
Mitigation checklist
- 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 months ago·verify at source
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