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bpf: Fix NULL-ptr-deref when showing a void BTF type

Type: advisorySource: Official CVE List1 source record

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NULL-ptr-deref when showing a void BTF type btf_modifier_show() resolves the modifier and then calls btf_type_ops(t)->show() unconditionally. For the void type (type_id 0, BTF_KIND_UNKN) kind_ops[] has no entry, so ->show is NULL. A "const void" (a modifier resolving to void) cannot be a map key or value - map_check_btf() rejects it because void has no size - so the map dump path does not reach it. But bpf_snprintf_btf() takes a type_id straight from the BPF program, and passing such a "const void" from the vmlinux BTF NULL-derefs: KASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f] RIP: 0010:btf_modifier_show (kernel/bpf/btf.c:2914) Call Trace: btf_type_show (kernel/bpf/btf.c:8251) btf_type_snprintf_show (kernel/bpf/btf.c:8321) 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:94) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) Fall back to btf_df_show() when the resolved type has no show op; it emits the "" placeholder already used for kinds like FWD and FUNC. bpf_snprintf_btf() then returns the length as usual.

Announced Source revision 1
Original source ↗

CVE-2026-98064

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-98064

Linux

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
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Prerequisites
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Linux

Source reference: /containers/cna/affected/1/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "cf528f2d7a0a54f2a3c6d439cfa3c8d7dfe90d8d",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "adb15557a641cb8a31f83e5f62bd12042b138c7b",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "62b00074b58ccf43f61f70f2cfcac80937b530c6",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "86d86f9fcf62dd3654090fbf3cf7ae5f42aa0706",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "717abdfd1d559d01fdd102023f0a990fb0437240",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "98f1cb95221332139acf514350ae2cae3b8656c5",
        "versionType": "git"
      },
      {
        "status": "affected",
        "version": "c4d0bfb45068d853a478b9067a95969b1886a30f",
        "lessThan": "5324f4e75ff6e9c2ca2e267c5f34f0937f9d0ac9",
        "versionType": "git"
      },
      {
        "status": "affected",
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        "lessThan": "4ea508b9ebd78bce7f212166d2e2cba66b875f08",
        "versionType": "git"
      }
    ],
    "programFiles": [
      "kernel/bpf/btf.c"
    ],
    "defaultStatus": "unaffected"
  },
  {
    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
    "vendor": "Linux",
    "product": "Linux",
    "versions": [
      {
        "status": "affected",
        "version": "5.10"
      },
      {
        "status": "unaffected",
        "version": "0",
        "lessThan": "5.10",
        "versionType": "semver"
      },
      {
        "status": "unaffected",
        "version": "5.10.271",
        "versionType": "semver",
        "lessThanOrEqual": "5.10.*"
      },
      {
        "status": "unaffected",
        "version": "5.15.222",
        "versionType": "semver",
        "lessThanOrEqual": "5.15.*"
      },
      {
        "status": "unaffected",
        "version": "6.1.189",
        "versionType": "semver",
        "lessThanOrEqual": "6.1.*"
      },
      {
        "status": "unaffected",
        "version": "6.6.158",
        "versionType": "semver",
        "lessThanOrEqual": "6.6.*"
      },
      {
        "status": "unaffected",
        "version": "6.12.111",
        "versionType": "semver",
        "lessThanOrEqual": "6.12.*"
      },
      {
        "status": "unaffected",
        "version": "6.18.53",
        "versionType": "semver",
        "lessThanOrEqual": "6.18.*"
      },
      {
        "status": "unaffected",
        "version": "7.2.7",
        "versionType": "semver",
        "lessThanOrEqual": "7.2.*"
      },
      {
        "status": "unaffected",
        "version": "7.3",
        "versionType": "original_commit_for_fix",
        "lessThanOrEqual": "*"
      }
    ],
    "programFiles": [
      "kernel/bpf/btf.c"
    ],
    "defaultStatus": "affected"
  }
]
Related CVEs
CVE-2026-98064

Source reference: /cveMetadata/cveId

Publisher severity

No explicit severity was provided.

Event
#38175 · Revision 1
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