Deadlock in Linux kernel - CVE-2026-98897

Vulnerability details

The vulnerability allows a remote user to cause a denial of service through prolonged delays in SMB file operations.

The vulnerability exists due to a lock-induced deadlock in the Linux kernel ksmbd lease-break handling code when processing a conflicting open against a read-handle lease cached by a cifs.ko client through deferred close. A remote user can trigger a conflicting file open to make the server wait for a lease-break acknowledgment while holding ci->m_lock for read, blocking the client's handle-close operation that requires the same lock for write and delaying completion until the 35-second timeout expires.

Affected software

How to mitigate CVE-2026-98897

External References

• https://git.kernel.org/stable/c/27a9bc968d4ae809a3f5ca2f2b136856ee613cb4
• https://git.kernel.org/stable/c/868c9038ffd4af39766d087f68c8f543a3f66635

Related Security Bulletins

• Deadlock in Linux kernel smb server
• Ubuntu update for linux-oem-7.0
• Ubuntu update for linux, linux-aws, linux-gcp and more