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CVE-2026-64422 In the Linux kernel, the following vulnerability has been resolved: net: ipv4: bound TCP reordering sysctl writes and…

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.

Affected products and versions

Product Affected versions Fixed in
Linux 7.2 earliest → < 7.2 7.2
Linux 7.1 earliest → < 7.1.4 7.1.4
Linux 6.18 earliest → < 6.18.39 6.18.39
Linux 6.12 earliest → < 6.12.96 6.12.96
Linux 6.6 earliest → < 6.6.145 6.6.145
Linux 6.1 earliest → < 6.1.178 6.1.178
Linux 5.15 earliest → < 5.15.212 5.15.212
Linux 5.10 earliest → < 5.10.261 5.10.261
Linux 2.6.24 No fix stated
Show the 3 other branches
Product Affected versions Fixed in
SIMATIC S7-1500 CPU 1518-4 PN/DP MFP 3.1 3.1.7 → latest No fix stated
SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP 3.1 3.1.7 → latest No fix stated
SIPLUS S7-1500 CPU 1518-4 PN/DP MFP 3.1 3.1.7 → latest No fix stated

References

Timeline

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