CVE-2025-38586 bpf, arm64: Fix fp initialization for exception boundary
A missing frame pointer initialization in the ARM64 BPF JIT can cause a kernel crash via page fault when exception boundaries are used.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2025-38586?
CVE-2025-38586 is a high-severity vulnerability in Linux kernel, published on 19 Aug 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
bpf, arm64: Fix fp initialization for exception boundary
In the ARM64 BPF JIT when prog->aux->exception_boundary is set for a BPF program, find_used_callee_regs() is not called because for a program acting as exception boundary, all callee saved registers are saved. find_used_callee_regs() sets `ctx->fp_used = true;` when it sees FP being used in any of the instructions.
For programs acting as exception boundary, ctx->fp_used remains false even if frame pointer is used by the program and therefore, FP is not set-up for such programs in the prologue. This can cause the kernel to crash due to a pagefault.
Fix it by setting ctx->fp_used = true for exception boundary programs as fp is always saved in such programs.
Weakness: CWE-476
Which versions are affected by CVE-2025-38586?
It affects 1 product.
Products include Linux kernel.
How do I fix CVE-2025-38586?
Apply the vendor's patch.
Is CVE-2025-38586 being exploited?
There is no known exploitation of CVE-2025-38586 in the wild and no public exploit code.
Other vulnerabilities in Linux kernel
Sources
Also known as BELL-CVE-2025-38586, DEBIAN-CVE-2025-38586, GHSA-rr3x-2w52-vv96, UBUNTU-CVE-2025-38586.