bpf: Fix NULL-ptr-deref when showing a void BTF type
Summary
| CVE | CVE-2026-98064 |
|---|---|
| State | PUBLISHED |
| Assigner | Linux |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-09-25 11:17:35 UTC |
| Updated | 2026-09-30 14:10:59 UTC |
| Description | 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: <TASK> 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) </TASK> Fall back to btf_df_show() when the resolved type has no show op; it emits the "<unsupported kind:N>" placeholder already used for kinds like FWD and FUNC. bpf_snprintf_btf() then returns the length as usual. |
Risk And Classification
EPSS: 0.001680000 probability, percentile 0.053990000 (date 2026-09-27)
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Linux | Linux | affected c4d0bfb45068d853a478b9067a95969b1886a30f 717abdfd1d559d01fdd102023f0a990fb0437240 git | Not specified |
| CNA | Linux | Linux | affected c4d0bfb45068d853a478b9067a95969b1886a30f 98f1cb95221332139acf514350ae2cae3b8656c5 git | Not specified |
| CNA | Linux | Linux | affected c4d0bfb45068d853a478b9067a95969b1886a30f 5324f4e75ff6e9c2ca2e267c5f34f0937f9d0ac9 git | Not specified |
| CNA | Linux | Linux | affected c4d0bfb45068d853a478b9067a95969b1886a30f 4ea508b9ebd78bce7f212166d2e2cba66b875f08 git | Not specified |
| CNA | Linux | Linux | affected 5.10 | Not specified |
| CNA | Linux | Linux | unaffected 5.10 semver | Not specified |
| CNA | Linux | Linux | unaffected 6.12.111 6.12.* semver | Not specified |
| CNA | Linux | Linux | unaffected 6.18.53 6.18.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.2.7 7.2.* semver | Not specified |
| CNA | Linux | Linux | unaffected 7.3-rc2 * original_commit_for_fix | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| git.kernel.org/stable/c/4ea508b9ebd78bce7f212166d2e2cba66b875f08 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/98f1cb95221332139acf514350ae2cae3b8656c5 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/5324f4e75ff6e9c2ca2e267c5f34f0937f9d0ac9 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| git.kernel.org/stable/c/717abdfd1d559d01fdd102023f0a990fb0437240 | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 | git.kernel.org | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
There are currently no legacy QID mappings associated with this CVE.