#VU105134 Use-after-free in Linux kernel - CVE-2025-21812

Vulnerability identifier: #VU105134

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-2025-21812

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 ax25_rt_autobind() function in net/ax25/ax25_route.c, within the ax25_send_frame() and ax25_queue_xmit() functions in net/ax25/ax25_out.c, within the ax25_ip_xmit() function in net/ax25/ax25_ip.c, within the ax25_dev_device_up() and ax25_dev_device_down() functions in net/ax25/ax25_dev.c, within the ax25_fillin_cb_from_dev() and ax25_setsockopt() functions in net/ax25/af_ax25.c. A local user can escalate privileges on the system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Linux kernel: 6.13, 6.13.1

---

External links
https://git.kernel.org/stable/c/2802ed4ced27ebd474828fc67ffd7d66f11e3605
https://git.kernel.org/stable/c/7705d8a7f2c26c80973c81093db07c6022b2b30e
https://git.kernel.org/stable/c/8937f5e38a218531dce2a89fae60e3adcc2311e1
https://git.kernel.org/stable/c/95fc45d1dea8e1253f8ec58abc5befb71553d666
https://git.kernel.org/stable/c/c2531db6de3c95551be58878f859c6a053b7eb2e
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.13.2

---

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.