CVE-2026-99999

ipv4: validate checksum_start before completing checksum

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.

Affected

Linux

CVSS v3.1 CNA

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

EPSS

0.21% chance of exploitation in the next 30 days, 11th percentile

Published

2026-10-15

Updated

2026-10-17

Proof-of-concept exploits (2)

• PeronGH/CVE-2026-99999
• 01luyicheng/CVE-2026-99999

References

• CVE Record
• NVD entry

Related

• CVE-2026-43074