CVE-2026-93270
Received Received - Intake

BPF Interpreter Fallback Bypass in Linux Kernel

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: kernel.org

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().

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-24
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-93270
EUVD
EUVD-2026-86142

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

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Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This is a Linux kernel vulnerability where the BPF interpreter fails to handle a specific instruction (BPF_MOV64_PERCPU_REG) correctly. The interpreter ignores an offset value meant to indicate a per-CPU memory access, leading to a page fault when the kernel tries to read invalid memory. The fix requires JIT compilation for this instruction to prevent interpreter fallback.

Impact Analysis

This vulnerability could cause system crashes (kernel oops) when certain BPF programs are executed. It may lead to denial-of-service conditions if untrusted code triggers the faulty instruction. Systems using BPF features like tracing or networking could be affected.

Mitigation Strategies

Update the Linux kernel to a patched version that resolves this BPF interpreter issue. Disable BPF interpreter fallback by ensuring JIT is enabled for BPF programs. Monitor system logs for page faults or kernel oops related to BPF operations.

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