bpf: Don't infer non-NULL from a pointer with an unbounded offset
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: Don't infer non-NULL from a pointer with an unbounded offset reg_not_null() decides that a register holds a non-NULL value by looking at its type alone. For pointer types that allow arithmetic the type only guarantees a non-NULL base, in case of an unbound offset the runtime offset value might still add up to NULL. Consider the followng program: r6 = bpf_map_lookup_elem(map, &0); /* present */ if (r6 == 0) return 0; r7 = bpf_map_lookup_elem(map, &1); /* absent, NULL at runtime */ r8 = r7; r8 -= r6; /* pointer - pointer: unknown scalar, -r6 */ r8 <<= 1; r8 >>= 1; /* any non-negative offset is accepted by */ /* check_reg_sane_offset_ptr() */ r6 += r8; /* verifier: map value; runtime: zero */ if (r7 != r6) return 0; *(u8 *)(r7 + 0); /* r7 is inferred non-NULL, both are zero */ At runtime both registers are zero, the comparison is true and the load faults with NULL pointer dereference. Require the offset to be within +-BPF_MAX_VAR_OFF in reg_not_null().
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 6.6.160, 6.12.114, 6.18.57, 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-2026-98043
- 2026-10-03 Alias added: GHSA-w7pv-jwfv-f7cm
- 2026-10-16 Fix available: Linux/[email protected], Linux/Linux@65bea674f43c09c0eda033a140dfac6a2842a19f · CNA
- 2026-10-16 1 new reference · CNA
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Fix available: Linux/Linux@019d845a08b8ccfe8eefaaf4bca6870f2b8c58ae, Linux/[email protected], Linux/[email protected] +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-11-06 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/8b414dbe97fcefd116e5a620c3bd9993014aa4ce
- https://git.kernel.org/stable/c/019d845a08b8ccfe8eefaaf4bca6870f2b8c58ae
- https://git.kernel.org/stable/c/65bea674f43c09c0eda033a140dfac6a2842a19f
- https://git.kernel.org/stable/c/cb6642048739bf4ee5aa09fe465511f1e87caa63
- https://git.kernel.org/stable/c/67b529f521a6676cdfc78b91b0217d7eaa84216b
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Sources
- CVE-2026-98043 · CVE Program
- CVE-2026-98043 · NVD
- FIRST EPSS
- GHSA-w7pv-jwfv-f7cm · GitHub Advisory Database · CC BY 4.0
- CVE-2026-98043 · Red Hat security data · CC BY 4.0
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