CVE-2026-98063 (GCVE-0-2026-98063)
Vulnerability from cvelistv5
Published
2026-09-25 10:24
Modified
2026-10-19 09:13
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NULL-ptr-deref in btf_var_show() btf_var_show() calls btf_type_id_resolve() unconditionally, which dereferences btf->resolved_ids. That is NULL for a base BTF - e.g. the vmlinux BTF that bpf_snprintf_btf() renders against - since base BTF is not resolved during parsing. btf_modifier_show() guards this with 'if (btf->resolved_ids)', but btf_var_show() does not. A BPF program that passes the type_id of a BTF_KIND_VAR from the vmlinux BTF to bpf_snprintf_btf() thus NULL-derefs: KASAN: probably user-memory-access in range [0x46638-0x4663f] RIP: 0010:btf_var_show (kernel/bpf/btf.c:2929) Call Trace: <TASK> btf_type_show (kernel/bpf/btf.c:8259) btf_type_snprintf_show (kernel/bpf/btf.c:8329) bpf_snprintf_btf (kernel/trace/bpf_trace.c:1047) bpf_prog_test_run_raw_tp (net/bpf/test_run.c:829) __sys_bpf (kernel/bpf/syscall.c:4804) do_syscall_64 (arch/x86/entry/syscall_64.c:84) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK> Resolve the var's type directly with btf_type_skip_modifiers() when resolved_ids is NULL, mirroring btf_modifier_show().
References
Impacted products
Vendor Product Version
Linux Linux Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
Version: c4d0bfb45068d853a478b9067a95969b1886a30f
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{
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          "programFiles": [
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix NULL-ptr-deref in btf_var_show()\n\nbtf_var_show() calls btf_type_id_resolve() unconditionally, which\ndereferences btf-\u003eresolved_ids. That is NULL for a base BTF - e.g. the\nvmlinux BTF that bpf_snprintf_btf() renders against - since base BTF is\nnot resolved during parsing. btf_modifier_show() guards this with\n\u0027if (btf-\u003eresolved_ids)\u0027, but btf_var_show() does not.\n\nA BPF program that passes the type_id of a BTF_KIND_VAR from the vmlinux\nBTF to bpf_snprintf_btf() thus NULL-derefs:\n\nKASAN: probably user-memory-access in range [0x46638-0x4663f]\nRIP: 0010:btf_var_show (kernel/bpf/btf.c:2929)\nCall Trace:\n \u003cTASK\u003e\n btf_type_show (kernel/bpf/btf.c:8259)\n btf_type_snprintf_show (kernel/bpf/btf.c:8329)\n bpf_snprintf_btf (kernel/trace/bpf_trace.c:1047)\n bpf_prog_test_run_raw_tp (net/bpf/test_run.c:829)\n __sys_bpf (kernel/bpf/syscall.c:4804)\n do_syscall_64 (arch/x86/entry/syscall_64.c:84)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e\n\nResolve the var\u0027s type directly with btf_type_skip_modifiers() when\nresolved_ids is NULL, mirroring btf_modifier_show()."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T09:13:13.031Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/5756450c9a702da0efb4a993d0a6766b965736f3"
        },
        {
          "url": "https://git.kernel.org/stable/c/e83fcbe3b5d4a1ffb0569bb7c280358065c6017a"
        },
        {
          "url": "https://git.kernel.org/stable/c/e0d6a06171633d3ee3f7a39b57e5c845fb2b79f2"
        },
        {
          "url": "https://git.kernel.org/stable/c/aec0a9c1579eb9edf534960be592d09481bd7ac3"
        },
        {
          "url": "https://git.kernel.org/stable/c/e472ae0d97865e2021ee668a13eab64013aebf23"
        },
        {
          "url": "https://git.kernel.org/stable/c/ca086264e98108b44fdf53971033811a48defe2b"
        },
        {
          "url": "https://git.kernel.org/stable/c/ea383b3ea56979ce54c8aa88e6ec67164986c401"
        },
        {
          "url": "https://git.kernel.org/stable/c/5403a383f52fc0905703b488f7c3db4b2447dc58"
        }
      ],
      "title": "bpf: Fix NULL-ptr-deref in btf_var_show()",
      "x_generator": {
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-98063",
    "datePublished": "2026-09-25T10:24:07.203Z",
    "dateReserved": "2026-09-25T10:19:56.073Z",
    "dateUpdated": "2026-10-19T09:13:13.031Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}


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