Integer Overflow or Wraparound Affecting linux-6.12 package, versions <6.12.100-1~deb12u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.13% (4th percentile)

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  • Snyk IDSNYK-ECHOLATEST-LINUX612-18579266
  • published7 Aug 2026
  • disclosed25 Jul 2026

Introduced: 25 Jul 2026

CVE-2026-64422  (opens in a new tab)
CWE-190  (opens in a new tab)

How to fix?

Upgrade Echo:latest linux-6.12 to version 6.12.100-1~deb12u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Echo. See How to fix? for Echo:latest relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

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

Reject invalid net.ipv4.tcp_reordering values before they reach TCP socket state. The sysctl is stored as an int but copied into the u32 tp-&gt;reordering field for new sockets, so negative writes wrap to large values.

With tcp_mtu_probing=2, the wrapped value can overflow the tcp_mtu_probe() size calculation and drive the MTU probing path into an out-of-bounds read. Route tcp_reordering writes through proc_dointvec_minmax() and require it to be at least 1. Also require tcp_max_reordering to be at least 1 so the configured maximum cannot become negative either.

When registering the table for a non-init network namespace, relocate extra2 pointers that refer into init_net.ipv4 so the tcp_reordering upper bound follows that namespace's tcp_max_reordering.

Harden tcp_mtu_probe() itself by computing size_needed as u64. This keeps the send queue and window checks from being bypassed through signed integer overflow.

CVSS Base Scores

version 3.1