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PatchSiren cyber security CVE debrief

CVE-2026-64007 Linux CVE debrief

A vulnerability in the Linux kernel has been patched. The vulnerability is related to the netfilter synproxy component. An issue was found with the synproxy_tstamp_adjust function, which could lead to a checksum update being written to the wrong location, resulting in either a write to freed slab memory or a packet being sent with an incorrect checksum. This issue could allow an attacker to cause a denial of service or potentially execute arbitrary code.

Vendor
Linux
Product
Unknown
CVSS
Unknown
CISA KEV
Not listed in stored evidence
Original CVE published
2026-07-19
Original CVE updated
2026-07-19
Advisory published
2026-07-19
Advisory updated
2026-07-19

Who should care

Users of the Linux kernel should be aware of this vulnerability and take steps to ensure their systems are updated with the latest patches. Operators of Linux-based systems, platform administrators, vulnerability management teams, and security teams should review the vulnerability and assess their exposure.

Technical summary

The synproxy_tstamp_adjust function in the Linux kernel's netfilter component was found to have a vulnerability. The function rewrites the TCP timestamp option in place and then updates the TCP checksum. However, between obtaining the TCP header pointer and using it, the function calls skb_ensure_writable, which can free the old skb->head. This can cause the cached TCP header pointer to become stale, leading to a checksum update being written to the wrong location. The issue affects Linux kernel versions and could be exploited remotely.

Defensive priority

High

Recommended defensive actions

  • Apply the latest Linux kernel patches
  • Ensure systems are updated with the latest security patches
  • Monitor systems for potential exploitation attempts
  • Review compensating controls for exposed systems while remediation is scheduled and verified
  • Check relevant monitoring, detection, and logs for exposed assets that need extra review
  • Track exceptions, retest remediated assets, and close the item only after evidence is documented
  • Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record was published on 2026-07-19T16:17:40.407Z and has not been modified since then. The NVD entry is currently Received. Evidence is limited to CVE and NVD details. Defenders should verify system patch levels and review vulnerability context with Linux kernel maintainers and other sources for further information.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-07-19T16:17:40.407Z and has not been modified since then.