CVE-2026-72492 ksmbd: fix use-after-free in same_client_has_lease()
A use-after-free in the Linux kernel's ksmbd module allows attackers to potentially execute code or escalate privileges via concurrent lease operations.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72492?
CVE-2026-72492 is a high-severity use after free vulnerability in Linux, published on 15 Aug 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free in same_client_has_lease()
same_client_has_lease() returns an opinfo pointer from ci->m_op_list after dropping ci->m_lock without taking a reference.
smb_grant_oplock() then dereferences that pointer in copy_lease() and when checking breaking_cnt. A concurrent close can remove the old lease from ci->m_op_list and drop the last reference before the caller uses the returned pointer, leading to a use-after-free.
Take a reference when same_client_has_lease() selects an existing lease, drop any previous match while scanning, and release the returned reference in smb_grant_oplock() after copying the lease state.
Which versions are affected by CVE-2026-72492?
How do I fix CVE-2026-72492?
Apply the vendor's patch.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-72492 being exploited?
There is no known exploitation of CVE-2026-72492 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72492, DEBIAN-CVE-2026-72492, GHSA-h9qg-8gf5-6w98, UBUNTU-CVE-2026-72492.