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CVE-2026-64422

net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes

Published Jul 25, 2026 · updated Oct 15, 2026 · Linux Linux

In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid values before they reach TCP socket state. The sysctl is stored as an but copied into the field for new sockets, so negative writes wrap to large values. With , the wrapped value can overflow the size calculation and drive the MTU probing path into an out-of-bounds read. Route writes through and require it to be at least 1. Also require to be at least 1 so the configured maximum cannot become negative either. When registering the table for a non-init network namespace, relocate pointers that refer into so the upper bound follows that namespace's . Harden itself by computing as . This keeps the send queue and window checks from being bypassed through signed integer overflow.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jul 25, 2026 · NIST NVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid values before they reach TCP socket state. The sysctl is stored as an but copied into the field for new sockets, so negative writes wrap to large values. With , the wrapped value can overflow the size calculation and drive the MTU probing path into an

  2. Oct 15, 2026 · NIST NVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid values before they reach TCP socket state. The sysctl is stored as an but copied into the field for new sockets, so negative writes wrap to large values. With , the wrapped value can overflow the size calculation and drive the MTU probing path into an

Affected

  • cpe linux/linux kernelversion unspecified
  • cpe linux/linux kernel2.6.24
  • vendor Linux Linuxversion unspecified

Sources

  • CIRCL Vulnerability LookupVulnerability recordCVE-2026-64422

    In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid values before they reach TCP socket state. The sysctl is stored as an but copied into the field for new sockets, so negative writes

    vulnerability.circl.lu
  • CVE.orgVulnerability recordCVE-2026-64422

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-64422

    30-day exploitation probability 0.1%

    first.org
  • NIST NVDVulnerability recordCVE-2026-64422

    In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes Reject invalid values before they reach TCP socket state. The sysctl is stored as an but copied into the `

    nvd.nist.gov

References