- Critical 9.3
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.
Scores
The facts
- Published
- 15 October 2026
- Last changed
- 16 October 2026
- NVD status
- Received
- Severity
- Critical, CVSS 9.3 out of 10 (version 3.1)
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H - Known exploited
- Not in the CISA Known Exploited Vulnerabilities catalogue in this build.
- EPSS
- 0.2% chance of exploitation activity in the next 30 days (percentile 11).
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References
- git.kernel.org/…/0fab003ef4698e0628060a45a48f14b43ba2a40a
- git.kernel.org/…/32a8b0adaa18e52aaa0b246b5ffe683075354dbb
- git.kernel.org/…/6785011f8b16abf40b1e9d8b2e332232b3e68822
- git.kernel.org/…/94524b7b32691de2e2ce162c04d6cbc9106e5cbf
- git.kernel.org/…/a464d950f31c89565cbaae038cc60db04fe01956
- CVE-2026-99999 in the NVD