#VU105010 NULL pointer dereference in Linux kernel - CVE-2025-21720

Vulnerability identifier: #VU105010

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-2025-21720

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 include/net/xfrm.h. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 6.6, 6.6 rc1, 6.6 rc2, 6.6 rc3, 6.6 rc4, 6.6 rc5, 6.6 rc6, 6.6.1, 6.6.2, 6.6.3, 6.6.4, 6.6.5, 6.6.6, 6.6.7, 6.6.8, 6.6.9, 6.6.10, 6.6.11, 6.6.12, 6.6.13, 6.6.14, 6.6.15, 6.6.16, 6.6.17, 6.6.18, 6.6.19, 6.6.20, 6.6.21, 6.6.22, 6.6.23, 6.6.24, 6.6.25, 6.6.26, 6.6.27, 6.6.28, 6.6.29, 6.6.30, 6.6.31, 6.6.32, 6.6.33, 6.6.34, 6.6.35, 6.6.36, 6.6.37, 6.6.38, 6.6.39, 6.6.40, 6.6.41, 6.6.42, 6.6.43, 6.6.44, 6.6.45, 6.6.46, 6.6.47, 6.6.48, 6.6.49, 6.6.50, 6.6.51, 6.6.52, 6.6.53, 6.6.54, 6.6.55, 6.6.56, 6.6.57, 6.6.58, 6.6.59, 6.6.60, 6.6.61, 6.6.62, 6.6.63, 6.6.64, 6.6.65, 6.6.66, 6.6.67, 6.6.68, 6.6.69, 6.6.70, 6.6.71, 6.6.72, 6.6.73, 6.6.74, 6.6.75

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External links
https://git.kernel.org/stable/c/600258d555f0710b9c47fb78d2d80a4aecd608cc
https://git.kernel.org/stable/c/6945701ca1572f81bc9bb46f624b02eabb3eaf3e
https://git.kernel.org/stable/c/981ad4c882096e7375b8c2181dd4c3ee58ea5bae
https://git.kernel.org/stable/c/c6e1b2cac24b2a4d1dd472071021bf00c26450eb
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.6.76

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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.