Executive brief
A vulnerability exists in the Linux kernel's ksmbd component, which provides SMB file sharing services. An attacker could exploit a memory management error to cause a system crash or potentially execute unauthorized code. This could lead to a complete loss of system availability or the compromise of sensitive data stored on the file server.
Technical details
A use-after-free vulnerability exists in the ksmbd module of the Linux kernel within the smb_lazy_parent_lease_break_close() function. The root cause is a race condition where the 'opinfo' pointer, obtained via rcu_dereference, is accessed after rcu_read_unlock() has been called. This allows a concurrent writer to free the memory before it is dereferenced (e.g., accessing opinfo->is_lease). An attacker can trigger this race condition over the network without authentication, potentially leading to remote code execution or a kernel panic. Patches have been released for multiple stable kernel branches including 6.6.y, 6.12.y, 6.18.y, and 6.19.y.
Affected products
- Linux Linux Kernel 6.13 to 6.18.19, 6.19 to 6.19.9, 6.6.32 to 6.6.130, 6.9 to 6.12.78
Timeline
- 2026-03-02: other: Vulnerability fixed in source code by Namjae Jeon
- 2026-05-08: disclosed: CVE published
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