#VU103959 Use-after-free in Linux kernel - CVE-2025-21700

Vulnerability identifier: #VU103959

Vulnerability risk: Low

CVSSv4.0: 4 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:U/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2025-21700

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 qdisc_lookup() function in net/sched/sch_api.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/46c59ec33ec98aba20c15117630cae43a01404cc
https://git.kernel.org/stable/c/73c7e1d6898ccbeee126194dcc05f58b8a795e70
https://git.kernel.org/stable/c/7e2bd8c13b07e29a247c023c7444df23f9a79fd8
https://git.kernel.org/stable/c/bc50835e83f60f56e9bec2b392fb5544f250fb6f

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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.