{"id":"CVE-2026-90269","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject load-acquire from pointers requiring fault protection\n\nA BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier,\nunlike a regular BPF_LDX, so…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject load-acquire from pointers requiring fault protection\n\nA BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier,\nunlike a regular BPF_LDX, so…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 880442305a3908589bf4d6fc1d79edb577ee497c < c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd","Linux >= 880442305a3908589bf4d6fc1d79edb577ee497c < 5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18","Linux >= 880442305a3908589bf4d6fc1d79edb577ee497c < 7db0a00445f1a40bacfe9b747405c11cb5f10fc9","Linux 6.15"],"published":"2026-09-17","updated":"2026-09-17","sourceUpdated":"2026-09-17T17:17:23.460","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-90269","references":[{"url":"https://git.kernel.org/stable/c/5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7db0a00445f1a40bacfe9b747405c11cb5f10fc9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"}],"tags":["nvd","cve.org"],"ingestedAt":"2026-09-17T16:21:47.838Z","epss":0.00198,"epssPercentile":0.09867,"slug":"CVE-2026-90269","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Reject load-acquire from pointers requiring fault protection\n\nA BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier,\nunlike a regular BPF_LDX, so the JIT emits a plain load with no exception\ntable entry and a fault panics the kernel instead of being handled.\n\nReject the source pointer types that a BPF_LDX would have had that fault\nprotection applied to, i.e. the ones bpf_convert_ctx_accesses() turns\ninto BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED,\nPTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY |\nPTR_UNTRUSTED.\n\nThis is reachable e.g. by loading ->mm out of a trusted task_struct\nyields an untrusted pointer to mm_struct, and it is NULL for a kernel\nthread:\n\n  [...]\n  SEC(\"tp_btf/sched_switch\")\n  int BPF_PROG(demo, bool preempt, struct task_struct *prev,\n               struct task_struct *next)\n  {\n      struct mm_struct *mm = next->mm;  /* untrusted */\n\n      out_ldx = (__u64)mm->pgd;         /* BPF_LDX      */\n      out_acq = load_acquire(&mm->pgd); /* BPF_LOAD_ACQ */\n      return 0;\n  }\n  [...]\n\nBoth dereference the same pointer, but only the BPF_LDX is protected\n(x86-64 JIT, jump targets shown prog-relative):\n\n  [...]\n  ; out_ldx = (__u64)mm->pgd;\n  17:   movq    $-10485760, %r10\n  1e:   movq    %rsi, %r11\n  21:   addq    $184, %r11\n  28:   subq    %r10, %r11\n  2b:   movabsq $140737498841088, %r10\n  35:   cmpq    %r10, %r11\n  38:   ja      0x3e                 <-- kernel addr?\n  3a:   xorl    %edi, %edi           <-- no: dst = 0, skip the load\n  3c:   jmp     0x45\n  3e:   movq    184(%rsi), %rdi      <-- yes: load + extable entry\n  [...]\n  ; load_acquire(&mm->pgd)\n  53:\tmovq    %rsi, %rdi\n  56:\tmovq    184(%rdi), %rax       <-- no check, no extable entry\n  [...]\n\nNote that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as\nbpf_insn_prepare_dump() rewrites it back to BPF_MEM.\n\nA PTR_TRUSTED pointer is deliberately not on the list. Such a load is\nnot converted either, but it does not need to be, since the pointer is\nguaranteed live, so load-acquire from it stays allowed.\n\nThe check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release\nerror messages are unchanged; writes (RMW / store-release) to such\npointers are already rejected elsewhere, so only load-acquire needs this.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}