CVE-2026-99999
Critical9.3In 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.
- CVSS
- 9.3v3.1
- EPSS (exploit probability)
- 0.2%11th pct
- CISA KEV
- Not listed
EPSS trendFIRST daily scores, last 90 days
Daily values
| Score date | EPSS | Percentile |
|---|---|---|
| 2026-10-20 | 0.2% | 10.8% |
| 2026-10-19 | 0.2% | 10.7% |
| 2026-10-18 | 0.2% | 10.6% |
| 2026-10-16 | 0.2% | 10.7% |
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Coverage1 article
References
- https://git.kernel.org/stable/c/0fab003ef4698e0628060a45a48f14b43ba2a40a
- https://git.kernel.org/stable/c/32a8b0adaa18e52aaa0b246b5ffe683075354dbb
- https://git.kernel.org/stable/c/6785011f8b16abf40b1e9d8b2e332232b3e68822
- https://git.kernel.org/stable/c/94524b7b32691de2e2ce162c04d6cbc9106e5cbf
- https://git.kernel.org/stable/c/a464d950f31c89565cbaae038cc60db04fe01956
- https://git.kernel.org/stable/c/a65f69e0f38ffbed1b128029e09097436416dc8b
- https://git.kernel.org/stable/c/c3e33464746166264334641dc850a36eef7e6326
- https://git.kernel.org/stable/c/f3e835af6226f1dd12160cbd696081e9b6155de0
- https://pwn.ai/blog/pwnescape
- https://vercel.com/blog/findings-from-the-1-million-dollar-vercel-sandbox-challenge
- http://www.openwall.com/lists/oss-security/2026/10/15/5