Red Hat Fixes Unbound DNS Cache and Availability Flaws on RHEL 10
Tech GuruQuick Answer
Apply RHSA-2026:97121 to applicable RHEL 10 systems using the entitled repository. Validate recursive resolution, DNSSEC and configured RPZ transfers after the supported service restart. Review resolver failures and retain configuration and package evidence.
Confirm Scope And Apply The Supported Remediation
What to do now: Record OS release, enabled repositories, architecture, installed Unbound packages, application dependencies and owners. Match the advisory product tree and fixed package identifiers to the system. Do not generalize the fixed source build to another RHEL stream, architecture or separately bundled copy. Install the supported binary package updates for RHSA-2026:97121 from the entitled Red Hat repositories. Retain the full epoch, version, release and architecture; the source build reference is not an instruction to install an SRPM. Validate recursive resolution, DNSSEC and configured RPZ transfers after the supported service restart. Review resolver failures and retain configuration and package evidence.
Last verified: 2026-11-10 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | Unbound packages on Red Hat Enterprise Linux 10 |
|---|---|
| Advisory | RHSA-2026:97121 |
| CVEs | CVE-2026-42923, CVE-2026-42960, CVE-2026-44608 |
| Authoritative release date | November 10, 2026 at 13:39:44 UTC, from Red Hat CSAF initial_release_date. |
| Authority revision date | Last substantive update recorded: 2026-11-10T13:39:44+00:00. CSAF generation timestamp: 2026-11-10T13:45:23+00:00; generation alone is not a material revision. |
| Affected versions | Package and architecture combinations identified by RHSA-2026:97121 in Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10). Red Hat does not state a universal lower affected-version boundary; confirm advisory applicability in the entitled repository. |
| Fixed version | Binary packages corresponding to source build unbound-0:1.26.1-2.el10_3 |
| CVSS base score | 5.9 maximum (official CVSS v3.1 base score) |
| CVSS severity | Medium (CVSS); Moderate (Red Hat impact) |
| Exploitation status | Red Hat does not state malicious exploitation in this advisory.; no exploitation claim is inferred. |
What Changed
Red Hat corrected Unbound DNSSEC processing, cache poisoning and RPZ reload vulnerabilities. The update addresses three CVEs with differing DNS input and configuration conditions.
What To Validate Now
- Inventory. Record OS release, enabled repositories, architecture, installed Unbound packages, application dependencies and owners.
- Establish applicability. Match the advisory product tree and fixed package identifiers to the system. Do not generalize the fixed source build to another RHEL stream, architecture or separately bundled copy.
- Remediate. Install the supported binary package updates for RHSA-2026:97121 from the entitled Red Hat repositories. Retain the full epoch, version, release and architecture; the source build reference is not an instruction to install an SRPM.
- Validate. Validate recursive resolution, DNSSEC and configured RPZ transfers after the supported service restart. Review resolver failures and retain configuration and package evidence.
- Retain evidence. Preserve asset and owner identifiers, the applicability decision, before-and-after versions, change approval, installation output, validation results, and any exception or rollback record.
Operational Cautions
Review Red Hat prerequisites and plan service availability before rollout. Validate running consumers and restart affected processes where required by the supported change procedure. Severity does not establish exploitation or customer applicability.
Evidence To Retain
- Exact product, release stream, package or application version, enabled feature, environment, and accountable owner.
- UTC timestamps, authority revision, approved change record, installer or package-manager output, and resulting version.
- Relevant logs and monitoring evidence, test results, exceptions, compensating controls, and rollback decisions.
Related TechGeeks Resources
Authoritative References
Correction policy: If the authority changes affected versions, fixed versions, severity, exploitation information, mitigations, or required action, TechGeeks will update this notice and its verification date.
Official Per-CVE Scores
- CVE-2026-42923: 5.3 MEDIUM (CVSS v3.1).
- CVE-2026-42960: 5.9 MEDIUM (CVSS v3.1).
- CVE-2026-44608: 5.9 MEDIUM (CVSS v3.1).
