Tracker / CVE-2026-64422
CVE-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 `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
| linux | linux_kernel |
|---|---|
| linux | linux_kernel · 2.6.24.1 → 5.10.261 |
| linux | linux_kernel · 5.11 → 5.15.212 |
| linux | linux_kernel · 5.16 → 6.1.178 |
| linux | linux_kernel · 6.13 → 6.18.39 |
| linux | linux_kernel · 6.19 → 7.1.4 |
| linux | linux_kernel · 6.2 → 6.6.145 |
| linux | linux_kernel · 6.7 → 6.12.96 |