CVE-2026-99999

9.3 CRITICAL 0.8% exploit odds No fix listed Other OS & kernel

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine without logging in. High risk of data exposure, data tampering, service disruption.
Exploit odds: 0.8% chance of exploitation in the next 30 days (EPSS).
Fix: No patch or advisory is linked yet. Look at mitigations or restrict exposure.

Timeline

2026-09-25 10:25 UTC ReservedThe CVE id was reserved by its CNA
2026-10-15 13:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-19 22:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.8% in the next 30 days (EPSS).
Severity: 9.3 CRITICAL (CVSS).
Fix: none linked yet, which raises it.

Details

Published: 2026-10-15 13:17 UTC
Last modified: 2026-10-19 22:17 UTC
Exploit probability: 0.8% · EPSS, next 30 days
Weakness: CWE-20 · Improper input validation
Record status: Received

Attack profile CVSS 3.1 · 9.3

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: None
Scope: Changed
Confidentiality: High
Integrity: High
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-99999.md and follow it. Check whether this project is affected by CVE-2026-99999. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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References

NVD record · CVE.org record