{"id":"CVE-2026-98064","summary":"bpf: Fix NULL-ptr-deref when showing a void BTF type","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix NULL-ptr-deref when showing a void BTF type\n\nbtf_modifier_show() resolves the modifier and then calls\nbtf_type_ops(t)-\u003eshow() unconditionally. For the void type (type_id 0,\nBTF_KIND_UNKN) kind_ops[] has no entry, so -\u003eshow is NULL.\n\nA \"const void\" (a modifier resolving to void) cannot be a map key or\nvalue - map_check_btf() rejects it because void has no size - so the map\ndump path does not reach it. But bpf_snprintf_btf() takes a type_id\nstraight from the BPF program, and passing such a \"const void\" from the\nvmlinux BTF NULL-derefs:\n\nKASAN: null-ptr-deref in range [0x0000000000000028-0x000000000000002f]\nRIP: 0010:btf_modifier_show (kernel/bpf/btf.c:2914)\nCall Trace:\n \u003cTASK\u003e\n btf_type_show (kernel/bpf/btf.c:8251)\n btf_type_snprintf_show (kernel/bpf/btf.c:8321)\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:94)\n entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121)\n \u003c/TASK\u003e\n\nFall back to btf_df_show() when the resolved type has no show op; it\nemits the \"\u003cunsupported kind:N\u003e\" placeholder already used for kinds like\nFWD and FUNC. bpf_snprintf_btf() then returns the length as usual.","modified":"2026-09-26T03:48:32.435043823Z","published":"2026-09-25T10:24:07.811Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98064.json"},"references":[{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4ea508b9ebd78bce7f212166d2e2cba66b875f08"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5324f4e75ff6e9c2ca2e267c5f34f0937f9d0ac9"},{"type":"WEB","url":"https://git.kernel.org/stable/c/717abdfd1d559d01fdd102023f0a990fb0437240"},{"type":"WEB","url":"https://git.kernel.org/stable/c/98f1cb95221332139acf514350ae2cae3b8656c5"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/98xxx/CVE-2026-98064.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-98064"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"c4d0bfb45068d853a478b9067a95969b1886a30f"},{"fixed":"717abdfd1d559d01fdd102023f0a990fb0437240"},{"fixed":"98f1cb95221332139acf514350ae2cae3b8656c5"},{"fixed":"5324f4e75ff6e9c2ca2e267c5f34f0937f9d0ac9"},{"fixed":"4ea508b9ebd78bce7f212166d2e2cba66b875f08"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98064.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.10.0"},{"fixed":"6.12.111"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.13.0"},{"fixed":"6.18.53"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.19.0"},{"fixed":"7.2.7"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-98064.json"}}],"schema_version":"1.9.0"}