bpf: Fix NULL-ptr-deref in btf_var_show()

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-98063
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-25 11:17:35 UTC
Updated2026-09-30 14:10:59 UTC
DescriptionIn 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().

Risk And Classification

EPSS: 0.001680000 probability, percentile 0.053990000 (date 2026-09-27)

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected c4d0bfb45068d853a478b9067a95969b1886a30f e472ae0d97865e2021ee668a13eab64013aebf23 git Not specified
CNA Linux Linux affected c4d0bfb45068d853a478b9067a95969b1886a30f ca086264e98108b44fdf53971033811a48defe2b git Not specified
CNA Linux Linux affected c4d0bfb45068d853a478b9067a95969b1886a30f ea383b3ea56979ce54c8aa88e6ec67164986c401 git Not specified
CNA Linux Linux affected c4d0bfb45068d853a478b9067a95969b1886a30f 5403a383f52fc0905703b488f7c3db4b2447dc58 git Not specified
CNA Linux Linux affected 5.10 Not specified
CNA Linux Linux unaffected 5.10 semver Not specified
CNA Linux Linux unaffected 6.12.111 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.53 6.18.* semver Not specified
CNA Linux Linux unaffected 7.2.7 7.2.* semver Not specified
CNA Linux Linux unaffected 7.3-rc2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/5403a383f52fc0905703b488f7c3db4b2447dc58 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ea383b3ea56979ce54c8aa88e6ec67164986c401 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/ca086264e98108b44fdf53971033811a48defe2b 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/e472ae0d97865e2021ee668a13eab64013aebf23 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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