Ubuntu Azure Kernel Updates Address Security Flaws
Tech GuruQuick Answer
Ubuntu published USN-8851-3 for Linux kernel (Azure) vulnerabilities on Ubuntu 18.04 (bionic) ESM. Ubuntu does not state a CVSS base score in this notice. Install the fixed source-package versions from the supported security or ESM channel and reboot into the new kernel.
Match USN-8851-3 To Ubuntu Releases And Update
What to do now: Inventory affected Ubuntu releases, compare installed source-package versions with USN-8851-3, install the supported updates and reboot, validate dependent workloads, and retain evidence.
Last verified: 2026-10-05 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | Linux kernel (Azure) vulnerabilities on Ubuntu 18.04 (bionic) ESM |
|---|---|
| Advisory | USN-8851-3 |
| CVEs | CVE-2025-38724, CVE-2026-53131, CVE-2026-53221 |
| Authoritative release date | 2026-10-05 14:43:13.257868 UTC |
| Authority revision date | 2026-10-05 14:43:13.257868 UTC |
| Affected versions | The Ubuntu releases and source packages enumerated in USN-8851-3: Ubuntu 18.04 (bionic) ESM. |
| Fixed version | bionic: linux-azure-5.4 5.4.0-1169.175~18.04.1 |
| CVSS base score | Not provided by the authority |
| CVSS severity | Not provided by the authority |
| Exploitation status | Not stated by the authority; no exploitation claim is inferred. |
What Changed
Several security issues were fixed in the Linux kernel. After a standard system update you need to reboot your computer to make all the necessary changes. ATTENTION: Due to an unavoidable ABI change the kernel updates have been given a new version number, which requires you to recompile and reinstall all third party kernel modules you might have installed. Unless you manually uninstalled the standard kernel metapackages (e.g. linux-generic, linux-generic-lts-RELEASE, linux-virtual, linux-powerpc), a standard system upgrade will automatically perform this as well.
What To Validate Now
- Inventory. Locate systems on Ubuntu 18.04 (bionic) ESM; record the installed source package, repository pocket, ESM entitlement where applicable, owner, exposure, and dependencies.
- Establish applicability. Match the Ubuntu codename and source package to USN-8851-3. Do not infer applicability from the binary package name, a generic kernel label, or the number of CVEs alone.
- Remediate. Install the fixed Ubuntu source-package versions listed in USN-8851-3 through the supported security or ESM channel. Reboot into the updated kernel.
- Validate. Confirm the installed running kernel and boot entry, test representative Linux kernel (Azure) functions and recovery paths, and document any exception.
- 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
A kernel package transaction alone does not activate the fix; coordinate reboot, third-party modules, Secure Boot, clustering, and rollback. Preserve package-manager output, before-and-after versions, validation results, and rollback evidence.
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.
