Use-after-free in Linux kernel - CVE-2021-47303
Published: May 31, 2024 / Updated: May 14, 2025
Vulnerability identifier: #VU90100
CSH Severity: Low
CVSS v4: 8.5 [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]
CVE-ID: CVE-2021-47303
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges on the system.
The vulnerability exists due to a use-after-free error within the jit_subprogs() function in kernel/bpf/verifier.c, within the bpf_prog_free_deferred() function in kernel/bpf/core.c, within the bpf_tail_call_direct_fixup() function in arch/x86/net/bpf_jit_comp.c. A local user can escalate privileges on the system.
Affected software
Linux kernel
How to mitigate CVE-2021-47303
Install update from vendor's website.
Linux kernel - addressed in versions 5.10.53, 5.13.5, 5.14
External References
- https://git.kernel.org/stable/c/a9f36bf3613c65cb587c70fac655c775d911409b
- https://git.kernel.org/stable/c/599148d40366bd5d1d504a3a8fcd65e21107e500
- https://git.kernel.org/stable/c/f263a81451c12da5a342d90572e317e611846f2c
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.10.53
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.13.5
- https://mirrors.edge.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.14