PT-2026-39040 · Linux · Linux Kernel

Published 2026-05-08 · Updated 2026-05-21 · CVE-2026-43379

Positive Technologies (AI Summary)

CVSS v3.1

9.8

Critical

Base vector

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

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

Description A use-after-free issue exists in the smb lazy parent lease break close() function. The opinfo pointer, obtained via rcu dereference(fp->f opinfo), is accessed after rcu read unlock() is called. This creates a race condition where concurrent writers may free the memory between the unlock and subsequent pointer dereferences, such as opinfo->is lease.

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

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2026-43379

Affected Products

Linux Kernel

References · 17

• https://ubuntu.com/security/CVE-2026-43379 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-43379 · Security Note
• https://osv.dev/vulnerability/BELL-CVE-2026-43379 · Vendor Advisory
• https://git.kernel.org/stable/c/eac3361e3d5dd8067b3258c69615888eb45e9f25 · Patch
• https://git.kernel.org/stable/c/b3568347c51c46e2cabc356bc34676df98296619 · Patch
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-43379 · Vendor Advisory
• https://git.kernel.org/stable/c/bf4d66d72e4a9e268c1012c331ce9eaedb5e2086 · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-43379 · Vendor Advisory
• https://git.kernel.org/stable/c/dbbd328cf58261ca239756fe1c0d10c9518d3399 · Patch
• https://git.kernel.org/stable/c/960699317d39f46611f4ebeb69edc567c1f4e6b6 · Patch
• https://security-tracker.debian.org/tracker/CVE-2026-43379 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-43379 · Security Note
• https://twitter.com/CVEnew/status/2052810991583248396 · Twitter Post
• https://t.me/cveNotify/164094 · Telegram Post
• https://twitter.com/hetmehtaa/status/2055151398283837677 · Twitter Post