#VU103028 NULL pointer dereference in Linux kernel - CVE-2025-21641

Vulnerability identifier: #VU103028

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-2025-21641

CWE-ID: CWE-476

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 NULL pointer dereference within the proc_blackhole_detect_timeout() function in net/mptcp/ctrl.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 6.12, 6.12.1, 6.12.2, 6.12.3, 6.12.4, 6.12.5, 6.12.6, 6.12.7, 6.12.8, 6.12.9

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External links
https://git.kernel.org/stable/c/4c74fbdc5ab95b13945be01e6065940b68222db7
https://git.kernel.org/stable/c/92cf7a51bdae24a32c592adcdd59a773ae149289
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.12.10
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.13

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Q & A

Can this vulnerability be exploited remotely?

No. This vulnerability can be exploited locally. The attacker should have authentication credentials and successfully authenticate on the system.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.