CVE-2026-43376

Summary

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().

Affected Software

VendorProductVersion RangeStatus
LinuxLinux296cb5457cc6f4a754c4ae29855f8a253d52bcc6 < 302fef75512b2c8329a3f5efab1ae7ba2562387aaffected
LinuxLinuxd54ab1520d43e95f9b2e22d7a05fc9614192e5a5 < 08aa9f3c8cf4d0bee44df540dfe34e8d64069f2caffected
LinuxLinux18b4fac5ef17f77fed9417d22210ceafd6525fc7 < 1d6abf145615dbfe267ce3b0a271f95e3780e18eaffected
LinuxLinux18b4fac5ef17f77fed9417d22210ceafd6525fc7 < ce8507ee82c888126d8e7565e27c016308d24cdeaffected
LinuxLinux18b4fac5ef17f77fed9417d22210ceafd6525fc7 < 1dfd062caa165ec9d7ee0823087930f3ab8a6294affected
LinuxLinuxd73686367ad68534257cd88a36ca3c52cb8b81d8affected
LinuxLinux6.6.88 < 6.6.130affected
LinuxLinux6.12.25 < 6.12.78affected
LinuxLinux6.14.4 < 6.15affected
LinuxLinux6.15affected
LinuxLinux0 < 6.15unaffected
LinuxLinux6.6.130 <= 6.6.*unaffected
LinuxLinux6.12.78 <= 6.12.*unaffected
LinuxLinux6.18.19 <= 6.18.*unaffected
LinuxLinux6.19.9 <= 6.19.*unaffected
LinuxLinux7.0 <= *unaffected

Weaknesses

References