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Vulnerabilities/CVE-2026-99999Public Intelligence Dossier
Source: Microsoft · Limited verification•Last verified: •Collection Degraded
CVE-2026-99999Unknown / EvaluatingCritical (raw)CVSS 9.3

ipv4: validate checksum_start before completing checksum

Published: 16 Oct 2026•Last updated: 16 Oct 2026, 08:13 PM IST•Source identifier: 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Dossier completeness: source-provided sections 3 / 3 · rule guidance not available. Missing source facts count as incomplete.
Official source
CISA KEV catalog
Unknown
KEV status was not determined.
CVSS score
9.3Critical (raw)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Metric sourceMicrosoft MSRC CVRF
EPSS probability
0.2%0.002
Percentile11th
Weakness type
—
No further CWE recorded
Remediation
Patch status unknown
No fixed version or KB recorded

Why It Matters

Analysis dossier

Why It Matters

In the Linux kernel, the following vulnerability has been resolved: ipv4: validate checksum_start before completing checksum If a packet with bad checksum metadata gets into the ipv4 stack, skb_checksum_help can corrupt the network header and cause a bunch of mischief. This was discovered and reported by Paulos, and has been reporoduced by others independently since. We really shouldn't allow such packets in, but as a defence in depth measure, let's also check before we complete the checksum. A more complete validation at input is forthcoming, but needs more work.

SOC priority

High Severity / Review

Actively exploited

Unknown

Publicly disclosed

Unknown

Risk basis: SOC ecosystem technology relevance; CRITICAL severity; Critical CVSS without confirmed KEV exploitation

Affected Products & Remediation

1 source-backed product
Affected products and versions (source)
  • azl3 kernel 6.6.157.1-1 on Azure Linux 3.0 · version range not provided by source · Microsoft MSRC · Source
Recorded patch / KBNot provided by source

Vendor or catalog guidance (source)

  • Microsoft MSRC: Release Notes

Known exploitation (source facts)

Only what a source states. Unknown means no source has said either way; it is not "not exploited".

CISA KEV
Unknown
Exploited (source statement)
Unknown
Publicly disclosed (source)
Unknown

Suggested hunting (rule-based inference)

SecOps Signal recommendation (rule-based inference). These steps are hunting hypotheses from the vulnerability class; they do not state or imply that exploitation occurred here or anywhere.

No rule-based guidance for this vulnerability class

CISA KEV Record

CISA KEV status was not determined for this record.

Change History & Source Data

— No recorded material change

CNA / source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Record status · verification
UPDATED · NVD API
CPE
Unknown

Evidence & Provenance

3 public sources
api.msrc.microsoft.comSource recordnvd.nist.govSource recordgit.kernel.orgSource record
Detection Hunting Query

— No published hunting query names this record. Browse community and library queries instead.

Open KQL Library

Correlated briefings

Microsoft Security Update Guide · Limited verificationOctober 2026 Security UpdatesPublished 13 Oct 2026
SecOps Signal surfaces public advisory facts only. A missing value means the source has not published it, not that your environment is unaffected. No tenant inventory is connected.