PT-2026-38977 · Linux · Linux Kernel

Published 2026-05-08 · Updated 2026-05-21 · CVE-2026-43326

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A deadlock occurs in the sched ext component due to the SCX KICK WAIT mechanism. The kick cpus irq workfn() function performs a busy-wait using smp cond load acquire() until the target CPU's kick sync advances. Since this process runs in a hardirq context (a high-priority interrupt handler that prevents other tasks from running on that CPU), the waiting CPU cannot reschedule, preventing its own kick sync from advancing. This can lead to a system-wide deadlock if multiple CPUs form a wait cycle.

Recommendations At the moment, there is no information about a newer version that contains a fix for this vulnerability.

Improper Locking

Weakness Enumeration

CWE-667

Related Identifiers

CVE-2026-43326

Affected Products

Linux Kernel

References · 14

• https://osv.dev/vulnerability/UBUNTU-CVE-2026-43326 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-43326 · Security Note
• https://ubuntu.com/security/CVE-2026-43326 · Vendor Advisory
• https://osv.dev/vulnerability/BELL-CVE-2026-43326 · Vendor Advisory
• https://git.kernel.org/stable/c/415cb193bb9736f0e830286c72a6fa8eb2a9cc5c · Patch
• https://git.kernel.org/stable/c/c3a7903f65cf4c7fb0477eb0f8b94f326a47fe54 · Patch
• https://cve.org/CVERecord?id=CVE-2026-43326 · Security Note
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-43326 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-43326 · Vendor Advisory
• https://twitter.com/infoflowcloud/status/2052812450563559706 · Twitter Post
• https://git.kernel.org/linus/415cb193bb9736f0e830286c72a6fa8eb2a9cc5c · Note
• https://twitter.com/CVEnew/status/2052811056242716799 · Twitter Post
• https://docs.bell-sw.com/security/cves/CVE-2026-43326 · Note
• https://t.me/cveNotify/163651 · Telegram Post