Vulnerability details

CVE-2026-64422

Linux LinuxSiemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFPSiemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFPSiemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP

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

CVSS 3.1
7.1High

Official description

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->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 scores

ScoreVersionSourceVector
7.1High 3.1 CVEProject cvelistV5 (CNA) (Linux) CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Affected products

VendorProductVersionsSource
Linux Linux 2.6.24 CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < 27ddf4486c7dbf5bdd393fa8bef6b67179796d98 CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < e81f805824a8109504fce090641b17d135b48cd1 CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < f0d88a4cd03affff6c08adf6c63964e235aede43 CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < bbae351c0f32f7c200249e4aa6561b2b419dcf69 CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < a094ac95d3b69adfa1676eb9c8eae6835d4f1671 CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < efb8763d7bbb40cff4cc55a6b62c3095a038149c CVEProject cvelistV5 (CNA)
Linux Linux 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf ≤ v < 99206ce2244f8a3ed64298d0667c9055845a5dc7 CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.6 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.7 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518-4 PN/DP MFP V3.1.7 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.6 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.6 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.7 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP V3.1.7 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.6 ≤ v CVEProject cvelistV5 (CNA)
Siemens SIPLUS S7-1500 CPU 1518-4 PN/DP MFP V3.1.7 ≤ v CVEProject cvelistV5 (CNA)

References and advisories

10
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Details

Published
2026-07-25
Last updated
2026-10-20
State
Published
Assigner (CNA)
Linux

Exploit prediction (EPSS)

0.13%
Probability of exploitation in 30 days
3.2%
Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable
No
Exploitation
None
Technical impact
Partial

Weaknesses (CWE)

  • CWE-190
    Integer Overflow or Wraparound