RHSA-2026:97497 - Security Advisory

Topic

An update for unbound is now available for Red Hat Enterprise Linux 9.

Red Hat Product Security has rated this update as having a security impact of Moderate. 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 DNS Cache Poisoning via Promiscuous Additional Section RRSet Acceptance (CVE-2026-42960)
• unbound: Unbound DNSSEC Validator NSEC3 Hash Calculation Limit Bypass via Negative Cache Code Path Leading to DoS (CVE-2026-42923)
• unbound: Unbound: Denial of Service due to locking inconsistency during RPZ XFR reload (CVE-2026-44608)

Bug Fix(es) and Enhancement(s):

• Update to latest 1.26 [rhel-9] (JIRA:RHEL-246537)

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.

Additional Changes:

For detailed information on changes in this release, see the Red Hat Enterprise Linux 9 Release Notes linked from 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 9 x86_64
• Red Hat Enterprise Linux for IBM z Systems 9 s390x
• Red Hat Enterprise Linux for Power, little endian 9 ppc64le
• Red Hat Enterprise Linux for ARM 64 9 aarch64
• Red Hat CodeReady Linux Builder for x86_64 9 x86_64
• Red Hat CodeReady Linux Builder for Power, little endian 9 ppc64le
• Red Hat CodeReady Linux Builder for ARM 64 9 aarch64
• Red Hat CodeReady Linux Builder for IBM z Systems 9 s390x

Fixes

• BZ - 2479821 - CVE-2026-42960 unbound: Unbound DNS Cache Poisoning via Promiscuous Additional Section RRSet Acceptance
• BZ - 2479825 - CVE-2026-42923 unbound: Unbound DNSSEC Validator NSEC3 Hash Calculation Limit Bypass via Negative Cache Code Path Leading to DoS
• BZ - 2480126 - CVE-2026-44608 unbound: Unbound: Denial of Service due to locking inconsistency during RPZ XFR reload

CVEs

• CVE-2026-42923
• CVE-2026-42960
• CVE-2026-44608

References

• https://access.redhat.com/security/updates/classification/#moderate
• https://docs.redhat.com/en/documentation/red_hat_enterprise_linux/9/html/9.9_release_notes/index