Vulnerability
CVE-2026-99999
Linux Kernel: memory corruption through unvalidated IPv4 checksum metadata
Most severe levelDEFCON 3 · Substantial risk
Official data
- CVSS 3.1
- 9.3 · critical
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-20
- EPSS
- 0.79% probability of exploitation in the next 30 days, higher than 56% of CVEs
- CISA KEV catalogue
- No
Sources: NVD (CVSS, weakness, publication), FIRST (EPSS), CISA (KEV catalogue).
Data read on 5 November 2026.
Timeline
- 15 October 2026Published on NVD
- 19 October 2026First in the DefenceLevel briefing
In DefenceLevel briefings10 days
- 5 November 2026Other exploited vulnerabilitiesDEFCON 4
- 4 November 2026Other exploited vulnerabilitiesDEFCON 4
- 3 November 2026New in the last 24 hoursDEFCON 4
- 2 November 2026Still ongoingDEFCON 4
- 1 November 2026Still ongoingDEFCON 4
- 31 October 2026New in the last 24 hoursDEFCON 3
- 22 October 2026Still ongoingDEFCON 4
- 21 October 2026Still ongoingDEFCON 4
- 20 October 2026New in the last 24 hoursDEFCON 3
- 19 October 2026Worth watching
Last 12 months.
The full analysis is in the briefingThe full analysis is in your archive
Why it matters now, who is affected and what to do: every day at 05:00 UTC, for subscribers.Why it matters, who is affected and what to do, as in the daily briefing.