VulnerabilityPublished 25 Sep 2026Updated 19 Oct 2026

CVE-2026-98132: Linux kernel · bpf: don't downgrade half-dead scalar zero spills to STACK_ZERO

Affects Linux kernelSource CVE Database V5

Not known to be exploited : upgrade to 436fa689630b741a77ef8c4a6f426479affd5bac or 2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e when convenient.

Data as of 26 Oct 2026, 14:05 UTC

Severity

Unrated

Rated by Threat Radar · CVSS not yet scored by NVD

EPSS: 0.1% chance of exploitation in 30 days – higher than 1% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 436fa689630b741a77ef8c4a6f426479affd5bac, 2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Sep 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Linux kernel to 436fa689630b741a77ef8c4a6f426479affd5bac or 2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ be23266b4a08540aa43d8503a2ea10247c8daebe, < 436fa689630b741a77ef8c4a6f426479affd5bac	Fixed in 436fa689630b741a77ef8c4a6f426479affd5bac
LinuxLinux	Affected ≥ be23266b4a08540aa43d8503a2ea10247c8daebe, < 2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e	Fixed in 2f3536bff8823d3c5fdbbe15e17bfca696cc2b2e
LinuxLinux	Affected =7.1	Fixed in–

AI-suggested

A fix is available and has been applied in the Linux kernel versions identified by the fixed commit hashes. Users should update their Linux kernel to a version that includes these fixes to resolve the issue.

Description

A vulnerability in the Linux kernel's BPF verifier involves improper handling of scalar zero spills on the stack, where zero spills are downgraded to STACK_ZERO incorrectly. This flaw breaks precision propagation chains during verification. The issue has been fixed by avoiding the conversion of stack spills of zero to STACK_ZERO in the kernel code.

Impact

This vulnerability affects the internal verification logic of BPF programs in the Linux kernel, potentially leading to incorrect verification results due to broken precision propagation chains. There is no indication of direct exploitation or impact on system security beyond verification correctness. No known exploits in the wild have been reported.

Summary

The vulnerability in the Linux kernel relates to the BPF verifier's handling of scalar zero spills on the stack. Specifically, the function __clean_func_state() can downgrade scalar zero spills to STACK_ZERO under certain conditions, which breaks precision propagation chains. The patch fixes this by preventing the downgrade of stack spills of zero to STACK_ZERO, maintaining correct precision tracking. More complex fixes were considered but the simplest approach was chosen to resolve the issue.

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 26 Oct 2026, 12:41 UTC

Technical details

References

Community reviews

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