CVE-2026-43376
Linux Kernel use-after-free
- Published8 May 2026
Description
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free by using call_rcu() for oplock_info ksmbd currently frees oplock_info immediately using kfree(), even though it is accessed under RCU read-side critical sections in places like opinfo_get() and proc_show_files(). Since there is no RCU grace period delay between nullifying the pointer and freeing the memory, a reader can still access oplock_info structure after it has been freed. This can leads to a use-after-free especially in opinfo_get() where atomic_inc_not_zero() is called on already freed memory. Fix this by switching to deferred freeing using call_rcu().
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HAffected products
Remediation
- https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c
- https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e
- https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294
- https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a
- https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde
References
- https://git.kernel.org/stable/c/08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c
- https://git.kernel.org/stable/c/1d6abf145615dbfe267ce3b0a271f95e3780e18e
- https://git.kernel.org/stable/c/1dfd062caa165ec9d7ee0823087930f3ab8a6294
- https://git.kernel.org/stable/c/302fef75512b2c8329a3f5efab1ae7ba2562387a
- https://git.kernel.org/stable/c/ce8507ee82c888126d8e7565e27c016308d24cde
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-43376 being actively exploited?
CVE-2026-43376 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.65%.
How severe is CVE-2026-43376?
CVE-2026-43376 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.65% probability of exploitation.
Which products are affected by CVE-2026-43376?
Affected products include Linux Kernel.
How do I fix CVE-2026-43376?
Upgrade affected software to a fixed version, for example Linux Kernel 6.12.78 or later, then confirm no affected versions remain in your inventory.
How Secuno handles this
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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.