CVE-2026-23383

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing<br /> <br /> struct bpf_plt contains a u64 target field. Currently, the BPF JIT<br /> allocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT<br /> buffer.<br /> <br /> Because the base address of the JIT buffer can be 4-byte aligned (e.g.,<br /> ending in 0x4 or 0xc), the relative padding logic in build_plt() fails<br /> to ensure that target lands on an 8-byte boundary.<br /> <br /> This leads to two issues:<br /> 1. UBSAN reports misaligned-access warnings when dereferencing the<br /> structure.<br /> 2. More critically, target is updated concurrently via WRITE_ONCE() in<br /> bpf_arch_text_poke() while the JIT&amp;#39;d code executes ldr. On arm64,<br /> 64-bit loads/stores are only guaranteed to be single-copy atomic if<br /> they are 64-bit aligned. A misaligned target risks a torn read,<br /> causing the JIT to jump to a corrupted address.<br /> <br /> Fix this by increasing the allocation alignment requirement to 8 bytes<br /> (sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of<br /> the JIT buffer to an 8-byte boundary, allowing the relative padding math<br /> in build_plt() to correctly align the target field.