{"id":"CVE-2026-23383","title":"bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing\n\nstruct bpf_plt contains a u64 target field. Currently, the BPF JIT\nallocator requests an al…","severity":"high","cvss":7.8,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cvssSource":"cna","vendor":"Linux","product":"Linux","affected":["Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d","Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 80ad264da02cc4aee718e799c2b79f0f834673dc","Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 519b1ad91de5bf7a496f2b858e9212db6328e1de","Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 66959ed481a474eaae278c7f6860a2a9b188a4d6","Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < ef06fd16d48704eac868441d98d4ef083d8f3d07","Linux 6.0"],"published":"2026-03-25","updated":"2026-10-21","sourceUpdated":"2026-10-21T12:39:11.598Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-23383","references":[{"url":"https://git.kernel.org/stable/c/f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d"},{"url":"https://git.kernel.org/stable/c/80ad264da02cc4aee718e799c2b79f0f834673dc"},{"url":"https://git.kernel.org/stable/c/519b1ad91de5bf7a496f2b858e9212db6328e1de"},{"url":"https://git.kernel.org/stable/c/66959ed481a474eaae278c7f6860a2a9b188a4d6"},{"url":"https://git.kernel.org/stable/c/ef06fd16d48704eac868441d98d4ef083d8f3d07"}],"tags":["cve.org"],"epss":0.00129,"epssPercentile":0.02228,"ingestedAt":"2026-10-21T12:48:53.667Z","slug":"CVE-2026-23383","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing\n\nstruct bpf_plt contains a u64 target field. Currently, the BPF JIT\nallocator requests an alignment of 4 bytes (sizeof(u32)) for the JIT\nbuffer.\n\nBecause the base address of the JIT buffer can be 4-byte aligned (e.g.,\nending in 0x4 or 0xc), the relative padding logic in build_plt() fails\nto ensure that target lands on an 8-byte boundary.\n\nThis leads to two issues:\n1. UBSAN reports misaligned-access warnings when dereferencing the\n   structure.\n2. More critically, target is updated concurrently via WRITE_ONCE() in\n   bpf_arch_text_poke() while the JIT'd code executes ldr. On arm64,\n   64-bit loads/stores are only guaranteed to be single-copy atomic if\n   they are 64-bit aligned. A misaligned target risks a torn read,\n   causing the JIT to jump to a corrupted address.\n\nFix this by increasing the allocation alignment requirement to 8 bytes\n(sizeof(u64)) in bpf_jit_binary_pack_alloc(). This anchors the base of\nthe JIT buffer to an 8-byte boundary, allowing the relative padding math\nin build_plt() to correctly align the target field.\n\n## Affected\n\n- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < f5a41b61b5faae1965a5a2cb55322fe8f17e3b2d`\n- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 80ad264da02cc4aee718e799c2b79f0f834673dc`\n- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 519b1ad91de5bf7a496f2b858e9212db6328e1de`\n- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < 66959ed481a474eaae278c7f6860a2a9b188a4d6`\n- `Linux >= b2ad54e1533e91449cb2a371e034942bd7882b58 < ef06fd16d48704eac868441d98d4ef083d8f3d07`\n- `Linux 6.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":42.9,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}