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 dr
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.
- 🔗 git.kernel.org/stable/c/f0d88a4cd03affff6c08adf6c63964e2…
- 🔗 git.kernel.org/stable/c/27ddf4486c7dbf5bdd393fa8bef6b671…
- 🔗 git.kernel.org/stable/c/782708ca1ea1f68b8cbb5ea3a7f5f18d…
- 🔗 git.kernel.org/stable/c/e81f805824a8109504fce090641b17d1…
- 🔗 git.kernel.org/stable/c/99206ce2244f8a3ed64298d0667c9055…
- 🔗 git.kernel.org/stable/c/bbae351c0f32f7c200249e4aa6561b2b…
- 🔗 git.kernel.org/stable/c/a094ac95d3b69adfa1676eb9c8eae683…
- 🔗 git.kernel.org/stable/c/efb8763d7bbb40cff4cc55a6b62c3095…
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📊 Historien-Charts — Criticals-Trend · Vendors · EPSS-Verteilung
| Tier | 2026-08-29 | 2026-09-06 |
|---|---|---|
| ≥90 % | 4 | 0 |
| ≥50 % | 4 | 0 |
| ≥10 % | 3 | 0 |
| <10 % | 304 | 300 |
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 dr
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