bpf: Fix NULL-ptr-deref in btf_var_show()
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Partial Red Hat: 5 without a fix
No CVSS vector from any source. Fix status from CNA and Red Hat.
Summary
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().
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.111, 6.18.53, 7.2.7, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 8 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 2 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
Timeline
- 2026-10-02 Threatist record created from CVE-2026-98063
- 2026-10-03 Alias added: GHSA-h366-qqqg-44v8
- 2026-10-03 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@5756450c9a702da0efb4a993d0a6766b965736f3 +5 · CNA
- 2026-10-03 4 new references · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 8
- https://git.kernel.org/stable/c/5756450c9a702da0efb4a993d0a6766b965736f3
- https://git.kernel.org/stable/c/e83fcbe3b5d4a1ffb0569bb7c280358065c6017a
- https://git.kernel.org/stable/c/e0d6a06171633d3ee3f7a39b57e5c845fb2b79f2
- https://git.kernel.org/stable/c/aec0a9c1579eb9edf534960be592d09481bd7ac3
- https://git.kernel.org/stable/c/e472ae0d97865e2021ee668a13eab64013aebf23
- https://git.kernel.org/stable/c/ca086264e98108b44fdf53971033811a48defe2b
- https://git.kernel.org/stable/c/ea383b3ea56979ce54c8aa88e6ec67164986c401
- https://git.kernel.org/stable/c/5403a383f52fc0905703b488f7c3db4b2447dc58
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Sources
- CVE-2026-98063 · CVE Program
- CVE-2026-98063 · NVD
- FIRST EPSS
- GHSA-h366-qqqg-44v8 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98063 · Red Hat security data · CC BY 4.0
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