CVE-2026-99999
ipv4: validate checksum_start before completing checksum
Description
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.
INFO
Published Date :
Oct. 15, 2026, 1:17 p.m.
Last Modified :
Oct. 15, 2026, 1:17 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | CRITICAL | MITRE-CVE | ||||
| CVSS 3.1 | CRITICAL | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Update the Linux kernel to the latest version.
- Apply relevant security patches for the networking stack.
- Validate checksum metadata during packet processing.
- Reboot the system after applying updates.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-99999.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-99999 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-99999
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-99999 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-99999 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Oct. 15, 2026
Action Type Old Value New Value Added Description 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. Added CVSS V3.1 AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/99xxx/CVE-2026-99999.json">CVE-2026-99999</a> Added Reference https://git.kernel.org/stable/c/0fab003ef4698e0628060a45a48f14b43ba2a40a Added Reference https://git.kernel.org/stable/c/32a8b0adaa18e52aaa0b246b5ffe683075354dbb Added Reference https://git.kernel.org/stable/c/6785011f8b16abf40b1e9d8b2e332232b3e68822 Added Reference https://git.kernel.org/stable/c/94524b7b32691de2e2ce162c04d6cbc9106e5cbf Added Reference https://git.kernel.org/stable/c/a464d950f31c89565cbaae038cc60db04fe01956 Added Reference https://git.kernel.org/stable/c/a65f69e0f38ffbed1b128029e09097436416dc8b Added Reference https://git.kernel.org/stable/c/c3e33464746166264334641dc850a36eef7e6326 Added Reference https://git.kernel.org/stable/c/f3e835af6226f1dd12160cbd696081e9b6155de0 Added Reference https://pwn.ai/blog/Pwnescape Added Reference https://vercel.com/blog/findings-from-the-1-million-dollar-vercel-sandbox-challenge