CVE-2026-98063
Received
Received - Intake
NULL-ptr-deref in Linux Kernel BPF
Vulnerability report for CVE-2026-98063, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.
Publication date: 2026-09-25
Last updated on: 2026-09-25
Assigner: kernel.org
Description
Description
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().
CVSS Scores
EPSS Scores
| Probability: | |
| Percentile: |
Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| linux | kernel | * |
Helpful Resources
Exploitability
CWE
KEV
| CWE ID | Description |
|---|---|
| CWE-UNKNOWN |
