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NVD / CVE Program· CNA Linux

CVE-2026-98063: bpf: Fix NULL-ptr-deref in btf_var_show()

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.17% (FIRST EPSS).
  • Fixed version: Linux Linux 5403a383f52fc0905703b488f7c3db4b2447dc58, 5756450c9a702da0efb4a993d0a6766b965736f3, aec0a9c1579eb9edf534960be592d09481bd7ac3; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 5403a383f52fc0905703b488f7c3db4b2447dc58, 5756450c9a702da0efb4a993d0a6766b965736f3, aec0a9c1579eb9edf534960be592d09481bd7ac3; azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 6.6.158.1-1 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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().

—No exploit Fix available
Published
Sep 25, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 7th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

Is your version affected?

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—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.10affected
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before 5756450c9a702da0efb4a993d0a6766b965736f3affected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before e83fcbe3b5d4a1ffb0569bb7c280358065c6017aaffected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before e0d6a06171633d3ee3f7a39b57e5c845fb2b79f2affected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before aec0a9c1579eb9edf534960be592d09481bd7ac3affected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before e472ae0d97865e2021ee668a13eab64013aebf23affected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before ca086264e98108b44fdf53971033811a48defe2baffected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before ea383b3ea56979ce54c8aa88e6ec67164986c401affected · git
    • c4d0bfb45068d853a478b9067a95969b1886a30f and later · before 5403a383f52fc0905703b488f7c3db4b2447dc58affected · git
    • before 5.10not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.190-16.1.190-1
Debian:12linux-6.12before 6.12.111-1~deb12u16.12.111-1~deb12u1
Debian:13linuxbefore 6.12.111-16.12.111-1
Debian:14linuxbefore 7.2.7-17.2.7-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-98060Sep 25, 2026 · bpf: Reject resilient lock operations in rbtree callbacks
    0Monitor
  • ← EarlierCVE-2026-98061Sep 25, 2026 · bpf: Reject tail calls directly from callback frames
    0Monitor
  • Later →CVE-2026-98064Sep 25, 2026 · bpf: Fix NULL-ptr-deref when showing a void BTF type
    0Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux5403a383f52fc0905703b488f7c3db4b2447dc58Vendor (CNA)
Linux Linux5756450c9a702da0efb4a993d0a6766b965736f3Vendor (CNA)
Linux Linuxaec0a9c1579eb9edf534960be592d09481bd7ac3Vendor (CNA)
Linux Linuxca086264e98108b44fdf53971033811a48defe2bVendor (CNA)
Linux Linuxe0d6a06171633d3ee3f7a39b57e5c845fb2b79f2Vendor (CNA)
Linux Linuxe472ae0d97865e2021ee668a13eab64013aebf23Vendor (CNA)
Linux Linuxe83fcbe3b5d4a1ffb0569bb7c280358065c6017aVendor (CNA)
Linux Linuxea383b3ea56979ce54c8aa88e6ec67164986c401Vendor (CNA)
azl3 kernel 6.6.157.1-1 on Azure Linux 3.06.6.158.1-1 · Release NotesMicrosoft (MSRC)
debian:linux6.1.190-1 · Debian:12Package registry (OSV)
debian:linux6.12.111-1 · Debian:13Package registry (OSV)
debian:linux-6.126.12.111-1~deb12u1 · Debian:12Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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