CVE-2026-43127 Linux CVE debrief

Who should care

Linux kernel maintainers, Linux distribution maintainers, and users of Linux kernel versions 6.6.66 to 6.18.16 and 6.19 to 6.19.6 should assess exposure and prioritize patching or verification.

Why it matters

A circular locking dependency vulnerability in the Linux kernel's ntfs3 filesystem implementation can lead to a deadlock scenario. Linux kernel maintainers and users should assess exposure and prioritize patching or verification for affected versions.

• Verify Linux kernel versions and assess exposure
• Prioritize patching or verification for affected versions
• Monitor Linux kernel updates for further patches or advisories

Technical summary

The vulnerability occurs in the `run_unpack_ex` function of the Linux kernel's ntfs3 filesystem implementation. A circular locking dependency can lead to a deadlock scenario. The issue has been resolved by using `down_read_trylock()` instead of `down_read()` when acquiring `run_lock` in `run_unpack_ex()`. The vulnerability affects Linux kernel versions 6.6.66 to 6.18.16 and 6.19 to 6.19.6. Linux kernel maintainers and users should assess exposure and prioritize patching or verification for affected versions. The fix prevents the deadlock scenario by avoiding contention on `run_lock`.

Defensive priority

Linux kernel maintainers and users should assess exposure and prioritize patching or verification for Linux kernel versions 6.6.66 to 6.18.16 and 6.19 to 6.19.6.

Recommended defensive actions

• Assess exposure for Linux kernel versions 6.6.66 to 6.18.16 and 6.19 to 6.19.6
• Prioritize patching or verification for affected Linux kernel versions
• Monitor Linux kernel updates for further patches or advisories
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up.
• Review compensating controls for exposed systems while remediation is scheduled and verified.
• Check relevant monitoring, detection, and logs for exposed assets that need extra review.
• Track exceptions, retest remediated assets, and close the item only after evidence is documented.

Evidence notes

The CVE record and NVD vulnerability detail page provide information on the vulnerability, including its description, CVSS score, and affected versions. The Linux kernel's ntfs3 filesystem implementation has a circular locking dependency vulnerability in the `run_unpack_ex` function. The issue has been resolved by using `down_read_trylock()` instead of `down_read()` when acquiring `run_lock` in `run_unpack_ex()`. The vulnerability affects Linux kernel versions 6.6.66 to 6.18.16 and 6.19 to 6.19.6. Defenders should verify Linux kernel

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.