#VU106810 Double free in Linux kernel - CVE-2025-21955

Vulnerability identifier: #VU106810

Vulnerability risk: Low

CVSSv4.0: 4.3 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-21955

CWE-ID: CWE-415

Exploitation vector: Local

Exploit availability: No

Vulnerable software:
Linux kernel
Operating systems & Components / Operating system

Vendor: Linux Foundation

Description

The vulnerability allows a local user to perform a denial of service (DoS) attack.

The vulnerability exists due to a double free error within the handle_ksmbd_work() and queue_ksmbd_work() functions in fs/smb/server/server.c, within the __smb2_oplock_break_noti(), smb2_oplock_break_noti(), __smb2_lease_break_noti() and smb2_lease_break_noti() functions in fs/smb/server/oplock.c, within the ksmbd_conn_init_server_callbacks() function in fs/smb/server/connection.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 6.13 - 6.13.7

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External links
https://git.kernel.org/stable/c/09aeab68033161cb54f194da93e51a11aee6144b
https://git.kernel.org/stable/c/3aa660c059240e0c795217182cf7df32909dd917
https://git.kernel.org/stable/c/a4261bbc33fbf99b99c80aa3a2c5097611802980
https://git.kernel.org/stable/c/f17d1c63a76b0fe8e9c78023a86507a3a6d62cfa
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.13.8

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Q & A

Can this vulnerability be exploited remotely?

Is there known malware, which exploits this vulnerability?