CVE-2025-37776 ksmbd: fix use-after-free in smb_break_all_levII_oplock()

High 8.8 Published Updated

A use-after-free vulnerability in the Linux kernel's ksmbd module allows attackers to potentially execute code or escalate privileges via race conditions.

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-2025-37776?

CVE-2025-37776 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 smb_break_all_levII_oplock()

There is a room in smb_break_all_levII_oplock that can cause racy issues when unlocking in the middle of the loop. This patch use read lock to protect whole loop.

Weakness: CWE-416

Which versions are affected by CVE-2025-37776?

It affects 1 product.

Products include Linux kernel.

How do I fix CVE-2025-37776?

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-2025-37776 being exploited?

There is no known exploitation of CVE-2025-37776 in the wild and no public exploit code.

All Linux kernel vulnerabilities

Sources

Also known as BELL-CVE-2025-37776, DEBIAN-CVE-2025-37776, GHSA-68wc-qrqf-rfh5, ROOT-OS-DEBIAN-12-CVE-2025-37776, ROOT-OS-UBUNTU-2204-CVE-2025-37776, ROOT-OS-UBUNTU-2404-CVE-2025-37776 and 1 more.

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