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CVE-2026-98064

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

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, and 2 more
None on Exploit-DB, Metasploit or GitHub

Summary

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.

Timeline

  1. CVE published
  2. Record last updated

Affected versions

  • Linux Linux

    From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in cf528f2d7a0a54f2a3c6d439cfa3c8d7dfe90d8d; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in adb15557a641cb8a31f83e5f62bd12042b138c7b; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in 62b00074b58ccf43f61f70f2cfcac80937b530c6; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in 86d86f9fcf62dd3654090fbf3cf7ae5f42aa0706; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in 717abdfd1d559d01fdd102023f0a990fb0437240; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in 98f1cb95221332139acf514350ae2cae3b8656c5; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in 5324f4e75ff6e9c2ca2e267c5f34f0937f9d0ac9; From c4d0bfb45068d853a478b9067a95969b1886a30f · fixed in 4ea508b9ebd78bce7f212166d2e2cba66b875f08

  • Linux Linux

    5.10

  • KernelLinux

    From 5.10.0 · fixed in 5.10.271; From 5.11.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7

References 8

git.kernel.org