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CRITICAL

CVE-2026-99999

CVSS v3

9.3

CRITICAL

EPSS Score

—

exploit probability

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-99999 yet.

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published
2026-10-15
Last Modified
2026-10-15

Frequently asked questions

What is CVE-2026-99999?

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.

Is CVE-2026-99999 actively exploited?

Active exploitation of CVE-2026-99999 has not been confirmed.

What is the CVSS score for CVE-2026-99999?

CVE-2026-99999 has a CVSS v3 base score of 9.3 (CRITICAL severity), with vector string CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

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