{"id":"CVE-2026-98063","published":"2026-09-25T11:17:35.327","lastModified":"2026-09-25T11:17:35.327","description":"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->resolved_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'if (btf->resolved_ids)', 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 <TASK>\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 </TASK>\n\nResolve the var's type directly with btf_type_skip_modifiers() when\nresolved_ids is NULL, mirroring btf_modifier_show().","cvssScore":null,"cvssSeverity":null,"cvssVector":null,"cwes":[],"vendors":[],"products":[],"references":[{"url":"https://git.kernel.org/stable/c/5403a383f52fc0905703b488f7c3db4b2447dc58","tags":[]},{"url":"https://git.kernel.org/stable/c/ca086264e98108b44fdf53971033811a48defe2b","tags":[]},{"url":"https://git.kernel.org/stable/c/e472ae0d97865e2021ee668a13eab64013aebf23","tags":[]},{"url":"https://git.kernel.org/stable/c/ea383b3ea56979ce54c8aa88e6ec67164986c401","tags":[]}],"exploitRefs":[],"hasPoc":false,"ai":null}