Description
In the Linux kernel, the following vulnerability has been resolved:

bpf: Mark NULL kptr stores precise

check_map_kptr_access() permits a scalar store into an untrusted kptr
field only when the register is known to contain zero. Unlike other
verifier checks whose outcome depends on a scalar value, it does not mark
that register precise.

A state checkpoint reached with an imprecise zero can therefore prune a
second path that reaches the store with an arbitrary nonzero scalar. The
program can write attacker-controlled bits into the kptr field and load
them back as a PTR_TO_BTF_ID.

Call mark_chain_precision() before accepting a known-zero register. This
forces state equivalence to compare its scalar range and makes the verifier
visit and reject a path carrying a nonzero value.
Published: 2026-09-25
Score: 7.0 High
EPSS: < 1% Very Low
KEV: No
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Remediation

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Tracking

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Advisories

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History

Tue, 29 Sep 2026 13:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-843
References
Metrics threat_severity

None

cvssV3_1

{'score': 7.0, 'vector': 'CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H'}

threat_severity

Moderate


Fri, 25 Sep 2026 22:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-665

Fri, 25 Sep 2026 10:30:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: bpf: Mark NULL kptr stores precise check_map_kptr_access() permits a scalar store into an untrusted kptr field only when the register is known to contain zero. Unlike other verifier checks whose outcome depends on a scalar value, it does not mark that register precise. A state checkpoint reached with an imprecise zero can therefore prune a second path that reaches the store with an arbitrary nonzero scalar. The program can write attacker-controlled bits into the kptr field and load them back as a PTR_TO_BTF_ID. Call mark_chain_precision() before accepting a known-zero register. This forces state equivalence to compare its scalar range and makes the verifier visit and reject a path carrying a nonzero value.
Title bpf: Mark NULL kptr stores precise
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-09-25T10:23:49.352Z

Reserved: 2026-09-25T10:19:56.070Z

Link: CVE-2026-98034

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-09-25T11:17:32.123

Modified: 2026-09-25T11:17:32.123

Link: CVE-2026-98034

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-09-25T00:00:00Z

Links: CVE-2026-98034 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-29T20:15:07Z

Weaknesses