CVE-2026-23383

Description

In the Linux kernel, the following vulnerability has been resolved:bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearingstruct bpf_plt contains a u64 target field. Currently, the BPF JITallocator requests an alignment of 4 bytes (sizeof(u32)) for the JITbuffer.Because the base address of the JIT buffer can be 4-byte aligned (e.g.,ending in 0x4 or 0xc), the relative padding logic in build_plt() failsto ensure that target lands on an 8-byte boundary.This leads to two issues:1. UBSAN reports misaligned-access warnings when dereferencing the structure.2. More critically, target is updated concurrently via WRITE_ONCE() in bpf_arch_text_poke() while the JITd code executes ldr. On arm64, 64-bit loads/stores are only guaranteed to be single-copy atomic if they are 64-bit aligned. A misaligned target risks a torn read, causing the JIT to jump to a corrupted address.Fix this by increasing the allocation alignment requirement to 8 bytes(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base ofthe JIT buffer to an 8-byte boundary, allowing the relative padding mathin build_plt() to correctly align the target field.

Risk Information

Associated Vulnerability

Patch Details

References

https://nvd.nist.gov/vuln/detail/CVE-2023-1234
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2023-1234