#VU103027 NULL pointer dereference in Linux kernel - CVE-2025-21640

Vulnerability identifier: #VU103027

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-2025-21640

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_sctp_do_hmac_alg() function in net/sctp/sysctl.c. A local user can perform a denial of service (DoS) attack.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: All versions

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External links
https://git.kernel.org/stable/c/3cd0659deb9c03535fd61839e91d4d4d3e51ac71
https://git.kernel.org/stable/c/ad673e514b2793b8d5902f6ba6ab7e890dea23d5
https://git.kernel.org/stable/c/ea62dd1383913b5999f3d16ae99d411f41b528d4
https://git.kernel.org/stable/c/f0bb3935470684306e4e04793a20ac4c4b08de0b

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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.