{
  "affected": [
    {
      "ecosystem_specific": {
        "urgency": "not yet assigned"
      },
      "package": {
        "ecosystem": "Debian:14",
        "name": "linux"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "details": "In the Linux kernel, the following vulnerability has been resolved:  bpf: Reject load-acquire from pointers requiring fault protection  A BPF_LOAD_ACQ is not rewritten to a BPF_PROBE_MEM load by the verifier, unlike a regular BPF_LDX, so the JIT emits a plain load with no exception table entry and a fault panics the kernel instead of being handled.  Reject the source pointer types that a BPF_LDX would have had that fault protection applied to, i.e. the ones bpf_convert_ctx_accesses() turns into BPF_PROBE_MEM: a bare PTR_TO_BTF_ID, PTR_TO_BTF_ID | PTR_UNTRUSTED, PTR_TO_BTF_ID | MEM_ALLOC | PTR_UNTRUSTED and PTR_TO_MEM | MEM_RDONLY | PTR_UNTRUSTED.  This is reachable e.g. by loading -\u003emm out of a trusted task_struct yields an untrusted pointer to mm_struct, and it is NULL for a kernel thread:    [...]   SEC(\"tp_btf/sched_switch\")   int BPF_PROG(demo, bool preempt, struct task_struct *prev,                struct task_struct *next)   {       struct mm_struct *mm = next-\u003emm;  /* untrusted */        out_ldx = (__u64)mm-\u003epgd;         /* BPF_LDX      */       out_acq = load_acquire(\u0026mm-\u003epgd); /* BPF_LOAD_ACQ */       return 0;   }   [...]  Both dereference the same pointer, but only the BPF_LDX is protected (x86-64 JIT, jump targets shown prog-relative):    [...]   ; out_ldx = (__u64)mm-\u003epgd;   17:   movq    $-10485760, %r10   1e:   movq    %rsi, %r11   21:   addq    $184, %r11   28:   subq    %r10, %r11   2b:   movabsq $140737498841088, %r10   35:   cmpq    %r10, %r11   38:   ja      0x3e                 \u003c-- kernel addr?   3a:   xorl    %edi, %edi           \u003c-- no: dst = 0, skip the load   3c:   jmp     0x45   3e:   movq    184(%rsi), %rdi      \u003c-- yes: load + extable entry   [...]   ; load_acquire(\u0026mm-\u003epgd)   53:\tmovq    %rsi, %rdi   56:\tmovq    184(%rdi), %rax       \u003c-- no check, no extable entry   [...]  Note that BPF_PROBE_MEM is not visible in a bpftool xlated dump, as bpf_insn_prepare_dump() rewrites it back to BPF_MEM.  A PTR_TRUSTED pointer is deliberately not on the list. Such a load is not converted either, but it does not need to be, since the pointer is guaranteed live, so load-acquire from it stays allowed.  The check is gated on BPF_LOAD_ACQ so that atomic RMW and store-release error messages are unchanged; writes (RMW / store-release) to such pointers are already rejected elsewhere, so only load-acquire needs this.",
  "id": "DEBIAN-CVE-2026-90269",
  "modified": "2026-09-18T04:47:29.040646101Z",
  "published": "2026-09-17T17:17:23.460Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://security-tracker.debian.org/tracker/CVE-2026-90269"
    }
  ],
  "upstream": [
    "CVE-2026-90269"
  ]
}