#VU106110 Use-after-free in Linux kernel - CVE-2025-21887
Vulnerability identifier: #VU106110
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-2025-21887
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 ovl_link_up() function in fs/overlayfs/copy_up.c. A local user can escalate privileges on the system.
Mitigation
Install update from vendor's website.
Vulnerable software versions
Linux kernel: 5.15, 5.15 rc1, 5.15 rc2, 5.15 rc3, 5.15 rc4, 5.15 rc5, 5.15 rc6, 5.15 rc7, 5.15.0, 5.15.1, 5.15.2, 5.15.3, 5.15.4, 5.15.5, 5.15.6, 5.15.7, 5.15.8, 5.15.9, 5.15.10, 5.15.11, 5.15.12, 5.15.13, 5.15.14, 5.15.15, 5.15.16, 5.15.17, 5.15.18, 5.15.19, 5.15.20, 5.15.21, 5.15.22, 5.15.23, 5.15.24, 5.15.25, 5.15.26, 5.15.27, 5.15.28, 5.15.29, 5.15.30, 5.15.31, 5.15.32, 5.15.33, 5.15.34, 5.15.35, 5.15.36, 5.15.37, 5.15.38, 5.15.39, 5.15.40, 5.15.41, 5.15.42, 5.15.43, 5.15.44, 5.15.45, 5.15.46, 5.15.47, 5.15.48, 5.15.49, 5.15.50, 5.15.51, 5.15.52, 5.15.53, 5.15.54, 5.15.55, 5.15.56, 5.15.57, 5.15.58, 5.15.59, 5.15.60, 5.15.61, 5.15.62, 5.15.63, 5.15.64, 5.15.65, 5.15.66, 5.15.67, 5.15.68, 5.15.69, 5.15.70, 5.15.71, 5.15.72, 5.15.73, 5.15.74, 5.15.75, 5.15.76, 5.15.77, 5.15.78, 5.15.79, 5.15.80, 5.15.81, 5.15.82, 5.15.83, 5.15.84, 5.15.85, 5.15.86, 5.15.87, 5.15.88, 5.15.89, 5.15.90, 5.15.91, 5.15.92, 5.15.93, 5.15.94, 5.15.95, 5.15.96, 5.15.97, 5.15.98, 5.15.99, 5.15.100, 5.15.101, 5.15.102, 5.15.103, 5.15.104, 5.15.105, 5.15.106, 5.15.107, 5.15.108, 5.15.109, 5.15.110, 5.15.111, 5.15.112, 5.15.113, 5.15.114, 5.15.115, 5.15.116, 5.15.117, 5.15.118, 5.15.119, 5.15.120, 5.15.121, 5.15.122, 5.15.123, 5.15.124, 5.15.125, 5.15.126, 5.15.127, 5.15.128, 5.15.129, 5.15.130, 5.15.131, 5.15.132, 5.15.133, 5.15.134, 5.15.135, 5.15.136, 5.15.137, 5.15.138, 5.15.139, 5.15.140, 5.15.141, 5.15.142, 5.15.143, 5.15.144, 5.15.145, 5.15.146, 5.15.147, 5.15.148, 5.15.149, 5.15.150, 5.15.151, 5.15.152, 5.15.153, 5.15.154, 5.15.155, 5.15.156, 5.15.157, 5.15.158, 5.15.159, 5.15.160, 5.15.161, 5.15.162, 5.15.163, 5.15.164, 5.15.165, 5.15.166, 5.15.167, 5.15.168, 5.15.169, 5.15.170, 5.15.171, 5.15.172, 5.15.173, 5.15.174, 5.15.175, 5.15.176, 5.15.177, 5.15.178, 6.1, 6.1 rc1, 6.1 rc3, 6.1 rc7, 6.1.1, 6.1.2, 6.1.3, 6.1.4, 6.1.5, 6.1.6, 6.1.7, 6.1.8, 6.1.9, 6.1.10, 6.1.11, 6.1.12, 6.1.13, 6.1.14, 6.1.15, 6.1.16, 6.1.17, 6.1.18, 6.1.19, 6.1.20, 6.1.21, 6.1.22, 6.1.23, 6.1.24, 6.1.25, 6.1.26, 6.1.27, 6.1.28, 6.1.29, 6.1.30, 6.1.31, 6.1.32, 6.1.33, 6.1.34, 6.1.35, 6.1.36, 6.1.37, 6.1.38, 6.1.39, 6.1.40, 6.1.41, 6.1.42, 6.1.43, 6.1.44, 6.1.45, 6.1.46, 6.1.47, 6.1.48, 6.1.49, 6.1.50, 6.1.51, 6.1.52, 6.1.53, 6.1.54, 6.1.55, 6.1.56, 6.1.57, 6.1.58, 6.1.59, 6.1.60, 6.1.61, 6.1.62, 6.1.63, 6.1.64, 6.1.65, 6.1.66, 6.1.67, 6.1.68, 6.1.69, 6.1.70, 6.1.71, 6.1.72, 6.1.73, 6.1.74, 6.1.75, 6.1.76, 6.1.77, 6.1.78, 6.1.79, 6.1.80, 6.1.81, 6.1.82, 6.1.83, 6.1.84, 6.1.85, 6.1.86, 6.1.87, 6.1.88, 6.1.89, 6.1.90, 6.1.91, 6.1.92, 6.1.93, 6.1.94, 6.1.95, 6.1.96, 6.1.97, 6.1.98, 6.1.99, 6.1.100, 6.1.101, 6.1.102, 6.1.103, 6.1.104, 6.1.105, 6.1.106, 6.1.107, 6.1.108, 6.1.109, 6.1.110, 6.1.111, 6.1.112, 6.1.113, 6.1.114, 6.1.115, 6.1.116, 6.1.117, 6.1.118, 6.1.119, 6.1.120, 6.1.121, 6.1.122, 6.1.123, 6.1.124, 6.1.125, 6.1.126, 6.1.127, 6.1.128, 6.1.129, 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, 6.6.76, 6.6.77, 6.6.78, 6.6.79, 6.6.80, 6.12, 6.12.1, 6.12.2, 6.12.3, 6.12.4, 6.12.5, 6.12.6, 6.12.7, 6.12.8, 6.12.9, 6.12.10, 6.12.11, 6.12.12, 6.12.13, 6.12.14, 6.12.15, 6.12.16, 6.12.17, 6.13, 6.13.1, 6.13.2, 6.13.3, 6.13.4, 6.13.5
External links
https://git.kernel.org/stable/c/3594aad97e7be2557ca9fa9c931b206b604028c8
https://git.kernel.org/stable/c/4b49d939b5a79117f939b77cc67efae2694d9799
https://git.kernel.org/stable/c/60b4b5c1277fc491da9e1e7abab307bfa39c2db7
https://git.kernel.org/stable/c/64455c8051c3aedc71abb7ec8d47c80301f99f00
https://git.kernel.org/stable/c/a7c41830ffcd17b2177a95a9b99b270302090c35
https://git.kernel.org/stable/c/c84e125fff2615b4d9c259e762596134eddd2f27
https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.179
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.1.130
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.12.18
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.13.6
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.14
https://mirrors.edge.kernel.org/pub/linux/kernel/v6.x/ChangeLog-6.6.81
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.
