RHSA-2026:72183 - Security Advisory

Topic

An update for unbound is now available for Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support and Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On.

Red Hat Product Security has rated this update as having a security impact of Critical. A Common Vulnerability Scoring System (CVSS) base score, which gives a detailed severity rating, is available for each vulnerability from the CVE link(s) in the References section.

Description

The unbound packages provide a validating, recursive, and caching DNS or DNSSEC resolver.

Security Fix(es):

• unbound: Unbound: Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY (CVE-2026-81642)

For more details about the security issue(s), including the impact, a CVSS score, acknowledgments, and other related information, refer to the CVE page(s) listed in the References section.

Solution

For details on how to apply this update, which includes the changes described in this advisory, refer to:

https://access.redhat.com/articles/11258

Affected Products

• Red Hat Enterprise Linux for x86_64 - Extended Life Cycle Long Life 8.4 x86_64
• Red Hat Enterprise Linux Server - AUS 8.4 x86_64
• Red Hat Enterprise Linux for ARM 64 - Extended Life Cycle Long Life 8.4 aarch64
• Red Hat Enterprise Linux for Power, little endian - Extended Life Cycle Long Life 8.4 ppc64le
• Red Hat Enterprise Linux for IBM z Systems - Extended Life Cycle Long Life 8.4 s390x

Fixes

• BZ - 2535059 - CVE-2026-81642 unbound: Unbound: Heap buffer overflow and possible Remote Code Execution when digesting DNSKEY

CVEs

• CVE-2026-81642

References

• https://access.redhat.com/security/updates/classification/#critical