#VU104946 Use-after-free in Linux kernel - CVE-2025-21759

Vulnerability identifier: #VU104946

Vulnerability risk: Low

CVSSv4.0: 5.9 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-21759

CWE-ID: CWE-416

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 escalate privileges on the system.

The vulnerability exists due to a use-after-free error within the mld_send_cr() and igmp6_send() functions in net/ipv6/mcast.c. A local user can escalate privileges on the system.

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/087c1faa594fa07a66933d750c0b2610aa1a2946
https://git.kernel.org/stable/c/0bf8e2f3768629d437a32cb824149e6e98254381
https://git.kernel.org/stable/c/81b25a07ebf53f9ef4ca8f3d96a8ddb94561dd5a
https://git.kernel.org/stable/c/8e92d6a413feaf968a33f0b439ecf27404407458

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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.