CVE-2026-93270 bpf: Disallow interpreter fallback for BPF_ADDR_PERCPU insn
A local attacker can cause a kernel page fault and system crash by triggering a BPF interpreter fallback bug in the Linux kernel.
- 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-2026-93270?
CVE-2026-93270 is a denial of service vulnerability in Linux, published on 24 Sep 2026. 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: Disallow interpreter fallback for BPF_ADDR_PERCPU insn
The BPF_MOV64_PERCPU_REG insn requires JIT to emit native code to for 'dst_reg = src_reg + <percpu_base_off>'.
However, the interpreter ignores the 'off' at its ALU64_MOV_X label. The 'off' indicates the insn is BPF_MOV64_PERCPU_REG insn. Then, when the interpreter loads memory from the register, it will hit a page fault.
[ 2.545572] BUG: unable to handle page fault for address: ffffffffacaaf034 [ 2.546485] #PF: supervisor read access in kernel mode [ 2.547167] #PF: error_code(0x0000) - not-present page [ 2.547850] PGD 134e63067 P4D 134e63067 PUD 134e64063 PMD 10021c063 PTE 800ffffeca550062 [ 2.548912] Oops: Oops: 0000 [#1] SMP PTI
Set jit_required as true in order to disallow interpreter fallback in core.c::__bpf_prog_select_runtime(), if any BPF_ADDR_PERCPU insn is patched to the prog.
BTW, rename the helper bpf_map_supports_cpu_flags() to bpf_map_is_percpu_map().
Which versions are affected by CVE-2026-93270?
How do I fix CVE-2026-93270?
Apply the vendor's patch.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-93270 being exploited?
There is no known exploitation of CVE-2026-93270 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-93270, DEBIAN-CVE-2026-93270, GHSA-8fj9-mr7j-8hr6, UBUNTU-CVE-2026-93270.