What’s Vulnerable › Vulnerabilities

CVE-2026-43379: ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close()

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-08 · updated 2026-06-17
• Weakness: CWE-416

Description

In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free in smb_lazy_parent_lease_break_close() opinfo pointer obtained via rcu_dereference(fp->f_opinfo) is being accessed after rcu_read_unlock() has been called. This creates a race condition where the memory could be freed by a concurrent writer between the unlock and the subsequent pointer dereferences (opinfo->is_lease, etc.), leading to a use-after-free.

Affected products

• Linux kernel: from 6.6.32 before 6.6.130; from 6.9 before 6.12.78; from 6.13 before 6.18.19; from 6.19 before 6.19.9; 7.0-rc1, 7.0-rc2, 7.0-rc3 — fixed in 6.12.78, 6.18.19, 6.19.9, 6.6.130

How to fix

Upgrade to a fixed version: Linux kernel 6.12.78, 6.18.19, 6.19.9, 6.6.130. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/960699317d39f46611f4ebeb69edc567c1f4e6b6
• https://git.kernel.org/stable/c/b3568347c51c46e2cabc356bc34676df98296619
• https://git.kernel.org/stable/c/bf4d66d72e4a9e268c1012c331ce9eaedb5e2086
• https://git.kernel.org/stable/c/dbbd328cf58261ca239756fe1c0d10c9518d3399
• https://git.kernel.org/stable/c/eac3361e3d5dd8067b3258c69615888eb45e9f25

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