Ubuntu USN-8729-4 Fixes Linux kernel (Low Latency) Vulnerabilities
Tech GuruQuick Answer
Ubuntu's USN-8729-4 updates the low-latency 6.8 kernel on Ubuntu 22.04 and 24.04. The jammy source package is linux-lowlatency-hwe-6.8; noble uses linux-lowlatency. Apply the appropriate binary packages, then reboot. The ABI change also requires rebuilding and reinstalling installed third-party modules, as detailed below.
Confirm Scope And Apply The Supported Fix
What to do now: Record the low-latency kernel flavor, Ubuntu release, active kernel, and third-party modules. Prepare recovery access, install that release's update, and schedule the reboot with the owners of timing-sensitive workloads.
Last verified: 2026-09-22 UTC. Recheck the authoritative advisory and supported distribution channel before changing production.
Scope And Authority
| Product scope | Linux kernel (Low Latency) packages on Ubuntu 24.04 LTS (noble), Ubuntu 22.04 LTS (jammy) |
|---|---|
| Advisory | USN-8729-4 |
| CVEs | CVE-2025-71289, CVE-2026-23469, CVE-2026-31420, CVE-2026-31486, CVE-2026-31560, CVE-2026-46158, CVE-2026-46170, CVE-2026-46275, CVE-2026-46315, CVE-2026-52912, CVE-2026-52915, CVE-2026-52916, CVE-2026-52918, CVE-2026-52919, CVE-2026-52921, CVE-2026-52922, CVE-2026-52926, CVE-2026-52941, CVE-2026-53357, CVE-2026-64015, CVE-2026-64018, CVE-2026-64025, CVE-2026-64029, CVE-2026-64032, CVE-2026-64033, CVE-2026-64034, CVE-2026-64039, CVE-2026-64046, CVE-2026-64047, CVE-2026-64048, CVE-2026-64051, CVE-2026-64055, CVE-2026-64056, CVE-2026-64064, CVE-2026-64073, CVE-2026-64083, CVE-2026-64084, CVE-2026-64085, CVE-2026-64086, CVE-2026-64087, CVE-2026-64088, CVE-2026-64089, CVE-2026-64092, CVE-2026-64096, CVE-2026-64097, CVE-2026-64098, CVE-2026-64102, CVE-2026-64103, CVE-2026-64106, CVE-2026-64108, CVE-2026-64109, CVE-2026-64111, CVE-2026-64113, CVE-2026-64114, CVE-2026-64115, CVE-2026-64116, CVE-2026-64118, CVE-2026-64121, CVE-2026-64125, CVE-2026-64126, CVE-2026-64127, CVE-2026-64128, CVE-2026-64133, CVE-2026-64134, CVE-2026-64135, CVE-2026-64136, CVE-2026-64137, CVE-2026-64138, CVE-2026-64144, CVE-2026-64147, CVE-2026-64148, CVE-2026-64153, CVE-2026-64155, CVE-2026-64163, CVE-2026-64165, CVE-2026-64166, CVE-2026-64168, CVE-2026-64170, CVE-2026-64173, CVE-2026-64174, CVE-2026-64177, CVE-2026-64178, CVE-2026-64179, CVE-2026-64180, CVE-2026-64182, CVE-2026-64183, CVE-2026-64184, CVE-2026-64185, CVE-2026-64214, CVE-2026-64217, CVE-2026-64218, CVE-2026-64219, CVE-2026-64220, CVE-2026-64221, CVE-2026-64225, CVE-2026-64231, CVE-2026-64518 |
| Ubuntu advisory publication | 2026-09-22 13:19:16.917432 UTC |
| Recorded source timestamp (historical snapshot) | 2026-09-22 13:19:16.917432 UTC |
| Affected versions | The Ubuntu releases and packages enumerated in USN-8729-4: Ubuntu 24.04 LTS (noble), Ubuntu 22.04 LTS (jammy). |
| Fixed source-package versions | jammy: linux-lowlatency-hwe-6.8 6.8.0-139.139.1~22.04.1 / noble: linux-lowlatency 6.8.0-139.139.1 |
| 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. Identify jammy low-latency HWE 6.8 and noble low-latency installations, including standard versus 64k variants, installed image/metapackages, active versions, and workload owners.
- Establish applicability. Compare each deployment with the authority's affected-version statement: The Ubuntu releases and packages enumerated in USN-8729-4: Ubuntu 24.04 LTS (noble), Ubuntu 22.04 LTS (jammy). Do not infer applicability from product family or severity alone.
- Remediate. Use the advisory's binary package mapping for the installed flavor. The source versions are
6.8.0-139.139.1~22.04.1on jammy and6.8.0-139.139.1on noble; both include versioned linux-image packages. Do not treat the source name as an instruction to install every variant. - Validate. After reboot, confirm the fixed low-latency kernel is running and required third-party modules load. Test the timing-sensitive workload under its approved acceptance criteria; this review makes no latency or regression measurement claim.
- 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
Use the exact supported release stream and repository. Test dependencies, clusters, integrations, and rollback before broad deployment; a CVSS rating or reachable feature is not evidence of exploitation.
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.
