CVE-2026-90269

{
  "id": "CVE-2026-90269",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2026-09-17T17:17:23.460",
  "lastModified": "2026-10-19T09:19:20.507",
  "vulnStatus": "Received",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "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 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."
    }
  ],
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "unaffected",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "880442305a3908589bf4d6fc1d79edb577ee497c",
              "lessThan": "c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "880442305a3908589bf4d6fc1d79edb577ee497c",
              "lessThan": "5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18",
              "versionType": "git",
              "status": "affected"
            },
            {
              "version": "880442305a3908589bf4d6fc1d79edb577ee497c",
              "lessThan": "7db0a00445f1a40bacfe9b747405c11cb5f10fc9",
              "versionType": "git",
              "status": "affected"
            }
          ]
        },
        {
          "vendor": "Linux",
          "product": "Linux",
          "defaultStatus": "affected",
          "programFiles": [
            "kernel/bpf/verifier.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "versions": [
            {
              "version": "6.15",
              "status": "affected"
            },
            {
              "version": "0",
              "lessThan": "6.15",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "6.18.52",
              "lessThanOrEqual": "6.18.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.2.6",
              "lessThanOrEqual": "7.2.*",
              "versionType": "semver",
              "status": "unaffected"
            },
            {
              "version": "7.3",
              "lessThanOrEqual": "*",
              "versionType": "original_commit_for_fix",
              "status": "unaffected"
            }
          ]
        }
      ]
    }
  ],
  "metrics": {},
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/5f8ade6e9b7931fc9697394f1b2c4ae833f5ac18",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/7db0a00445f1a40bacfe9b747405c11cb5f10fc9",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c4c8de3bf48d3756ab0f910fe5cc4937d70efdcd",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ]
}