CVE-2026-98063: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NULL-ptr-deref in btf_var_show() btf_var_show() calls btf_type_id_resolve() unconditionally, which dereferences btf->resolved_ids. That is NULL for a base BTF - e.g. the vmlinux BTF that bpf_snprintf_btf() renders against - since base BTF is not resolved during parsing. btf_modifier_show() guards this with 'if (btf->resolved_ids)', but btf_var_show() does not. A BPF program that passes the type_id of a BTF_KIND_VAR from the vmlinux BTF to bpf_snprintf_btf() thus NULL-derefs: KASAN: probably user-memory-access in range [0x46638-0x4663f] RIP: 0010:btf_var_show (kernel/bpf/btf.c:2929) Call Trace: <TASK> btf_type_show (kernel/bpf/btf.c:8259) btf_type_snprintf_show (kernel/bpf/btf.c:8329) 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:84) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:121) </TASK> Resolve the var's type directly with btf_type_skip_modifiers() when resolved_ids is NULL, mirroring btf_modifier_show().

Affected products

• Linux Linux: from 5.10, before 5.10.271 (fixed in 5.10.271); from 5.11, before 5.15.222 (fixed in 5.15.222); from 5.16, before 6.1.189 (fixed in 6.1.189); from 6.2, before 6.6.158 (fixed in 6.6.158); from 6.7, before 6.12.111 (fixed in 6.12.111); from 6.13, before 6.18.53 (fixed in 6.18.53); …

Published 2026-09-25. Last modified 2026-10-03.