IM
IronMonkey Threat Research

CVE-2026-64422 HIGH

Published: 2026-07-25 | Last Modified: 2026-09-08 | Status: Modified

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 Metrics

Base Score: 7.1 (HIGH)

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Attack VectorLOCAL
Attack ComplexityLOW
Privileges RequiredLOW
User InteractionNONE
ScopeUNCHANGED
Confidentiality ImpactHIGH
Integrity ImpactNONE
Availability ImpactHIGH

Source: 416baaa9-dc9f-4396-8d5f-8c081fb06d67

Type: Secondary

Exploitability Score: 1.8

Impact Score: 5.2

Weaknesses

Source Type Description
[email protected] Primary
en CWE-190

Affected Products

Vendor Product Version Update Type
linux linux_kernel * <built-in method update of dict object at 0x7d23a5986480> Operating System
linux linux_kernel * <built-in method update of dict object at 0x7d23a5984b40> Operating System
linux linux_kernel * <built-in method update of dict object at 0x7d24246c1a40> Operating System
linux linux_kernel * <built-in method update of dict object at 0x7d24245a17c0> Operating System
linux linux_kernel * <built-in method update of dict object at 0x7d2424507100> Operating System
linux linux_kernel * <built-in method update of dict object at 0x7d2424506000> Operating System
linux linux_kernel * <built-in method update of dict object at 0x7d23a59850c0> Operating System
linux linux_kernel 2.6.24 <built-in method update of dict object at 0x7d24246c2e40> Operating System
linux linux_kernel 2.6.24 <built-in method update of dict object at 0x7d24246c1d00> Operating System
linux linux_kernel 2.6.24 <built-in method update of dict object at 0x7d23a5986d40> Operating System
linux linux_kernel 2.6.24 <built-in method update of dict object at 0x7d24246c3040> Operating System
linux linux_kernel 2.6.24 <built-in method update of dict object at 0x7d23a5984940> Operating System
linux linux_kernel 2.6.24 <built-in method update of dict object at 0x7d24604e1dc0> Operating System

Affected Configurations

Operator: OR

Vulnerable CPE
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.24:-:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.24:rc4:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.24:rc5:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.24:rc6:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.24:rc7:*:*:*:*:*:*
Yes cpe:2.3:o:linux:linux_kernel:2.6.24:rc8:*:*:*:*:*:*

References

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