CVE-2026-99999

Packet-header corruption via unchecked checksum-start metadata

Published Oct 15, 2026 · Updated Oct 15, 2026

Checksum handling in the Linux IPv4 stack allows attackers to corrupt packet headers via malformed checksum-offload metadata. The skb_checksum_help function writes a completed checksum without first ensuring that csum_start lies beyond the IPv4 header. Exploitation requires an interface that supplies this metadata and a reachable software checksum-completion path; broader consequences and the supplied CVE association remain unverified.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Checksum handling in the Linux IPv4 stack allows attackers to corrupt packet headers via malformed checksum-offload metadata. The skb_checksum_help function writes a completed checksum without first ensuring that csum_start lies beyond the IPv4 header. Exploitation requires an interface that supplies this metadata and a reachable software checksum-completion path; broader consequences and the supplied CVE association remain unverified.

The record

CVE
CVE-2026-99999
Published
Oct 15, 2026
Updated
Oct 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 15, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.6.27
  2. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <0fab003ef4698e0628060a45a48f14b43ba2a40a
  3. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <32a8b0adaa18e52aaa0b246b5ffe683075354dbb
  4. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <6785011f8b16abf40b1e9d8b2e332232b3e68822
  5. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <94524b7b32691de2e2ce162c04d6cbc9106e5cbf
  6. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <a464d950f31c89565cbaae038cc60db04fe01956
  7. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <a65f69e0f38ffbed1b128029e09097436416dc8b
  8. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <c3e33464746166264334641dc850a36eef7e6326
  9. Affected versionversion=f43798c27684ab925adde7d8acc34c78c6e50df8 <f3e835af6226f1dd12160cbd696081e9b6155de0

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.27; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <0fab003ef4698e0628060a45a48f14b43ba2a40a; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <32a8b0adaa18e52aaa0b246b5ffe683075354dbb; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <6785011f8b16abf40b1e9d8b2e332232b3e68822; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <94524b7b32691de2e2ce162c04d6cbc9106e5cbf; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <a464d950f31c89565cbaae038cc60db04fe01956; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <a65f69e0f38ffbed1b128029e09097436416dc8b; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <c3e33464746166264334641dc850a36eef7e6326; version=f43798c27684ab925adde7d8acc34c78c6e50df8 <f3e835af6226f1dd12160cbd696081e9b6155de0

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

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No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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