CVE-2025-37777 ksmbd: fix use-after-free in __smb2_lease_break_noti()
A use-after-free vulnerability in the Linux kernel's ksmbd module allows attackers to potentially execute code or escalate privileges via asynchronous lease break notifications.
- 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-2025-37777?
CVE-2025-37777 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2025. 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 __smb2_lease_break_noti()
Move tcp_transport free to ksmbd_conn_free. If ksmbd connection is referenced when ksmbd server thread terminates, It will not be freed, but conn->tcp_transport is freed. __smb2_lease_break_noti can be performed asynchronously when the connection is disconnected. __smb2_lease_break_noti calls ksmbd_conn_write, which can cause use-after-free when conn->ksmbd_transport is already freed.
Weakness: CWE-416
Which versions are affected by CVE-2025-37777?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-37777?
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-2025-37777 being exploited?
There is no known exploitation of CVE-2025-37777 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-37777, DEBIAN-CVE-2025-37777, GHSA-4748-h423-7xq4, ROOT-OS-DEBIAN-12-CVE-2025-37777, ROOT-OS-UBUNTU-2204-CVE-2025-37777, ROOT-OS-UBUNTU-2404-CVE-2025-37777 and 1 more.