CVE-2026-99999: ipv4: validate checksum_start before completing checksum
Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.
Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.
What it is
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.
Description quoted from the CVE record (assigned by Linux, published 2026-10-15).
Weakness: CWE-20 Improper Input Validation
How it can be exploited
Exploitable with local access with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
CISA assessment (SSVC): CISA has no evidence of exploitation. Automatable: no. Technical impact: total.
Public exploit evidence (Exploit Observer)
Exploit Observer evidence for this CVE has not been fetched yet.
Live scores
- EPSS
- 0.008
low predicted chance of attack - VEDAS
- 0.926
strong exploit evidence - On CISA KEV
- Not listed
- Detection rule
- None yet
Who is affected
| Product | Affected | Not affected |
|---|---|---|
| Linux Linux | from f43798c27684 before a464d950f31c (git commit) from f43798c27684 before 0fab003ef469 (git commit) from f43798c27684 before 94524b7b3269 (git commit) from f43798c27684 before a65f69e0f38f (git commit) from f43798c27684 before 32a8b0adaa18 (git commit) from f43798c27684 before f3e835af6226 (git commit) from f43798c27684 before c3e334647461 (git commit) from f43798c27684 before 6785011f8b16 (git commit) | Not stated |
| Linux Linux | version 2.6.27 | 0 is not affected (up to 2.6.27); 5.10.272 is not affected; 5.15.223 is not affected; 6.1.190 is not affected |
Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.
How to fix it
No fixed version or vendor advisory is listed in the CVE record yet. Watch the vendor’s security page.
How to detect it
There is no open VEDAS detection rule for this bug yet. It is listed on the detection gaps page if CISA has confirmed attacks.
Advisories on this CVE
- Docker Desktop 4.97.0 (CVE-2026-114409, CVE-2026-99999): third-party tokens in cleartext logs and a VM network-stack bug (full advisory)
- Docker Desktop 4.97.0: third-party tokens in cleartext logs and a VM network-stack corruption bug (CVE-2026-114409, CVE-2026-99999) (26 Oct 2026)
References
Other references
- https://git.kernel.org/stable/c/a464d950f31c89565cbaae038cc60db04fe01956
- https://git.kernel.org/stable/c/0fab003ef4698e0628060a45a48f14b43ba2a40a
- https://git.kernel.org/stable/c/94524b7b32691de2e2ce162c04d6cbc9106e5cbf
- https://git.kernel.org/stable/c/a65f69e0f38ffbed1b128029e09097436416dc8b
- https://git.kernel.org/stable/c/32a8b0adaa18e52aaa0b246b5ffe683075354dbb
- https://git.kernel.org/stable/c/f3e835af6226f1dd12160cbd696081e9b6155de0
- https://git.kernel.org/stable/c/c3e33464746166264334641dc850a36eef7e6326
- https://git.kernel.org/stable/c/6785011f8b16abf40b1e9d8b2e332232b3e68822
- 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
Other databases
Where this comes from
This advisory is generated automatically by VEDAS from: CVE.org record, cve-scores (EPSS and VEDAS). Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.
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