Risk Letters

Exploited vulnerability

CVE-2026-99999

TLP:CLEAR

Linux Kernel Improper Validation of Specified Quantity in Input

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

Facts

  • Vendor: Linux
  • Product: Kernel
  • CVSS: 9.3
  • EPSS (probability of exploitation within 30 days): 0.8 %
  • First known exploitation: 19 October 2026
  • First seen by Risk Letters: 15 October 2026

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Data: NVD (public domain), CISA KEV, FIRST EPSS, MITRE ATT&CK, AlienVault OTX. NVD