CVE-2026-64422

CVE CVE-2026-64422EUVD EUVD-2026-48966Published 2026-07-25T08:51:00.000ZLast changed 2026-08-05T12:41:52.000ZCVSS 7.1

What the advisory describes

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.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux patch: 0; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <99206ce2244f8a3ed64298d0667c9055845a5dc7; patch: 7.2-rc1; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <efb8763d7bbb40cff4cc55a6b62c3095a038149c; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <e81f805824a8109504fce090641b17d135b48cd1; patch: 7.1.4; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <27ddf4486c7dbf5bdd393fa8bef6b67179796d98; patch: 6.1.178; patch: 6.12.96; 2.6.24; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <a094ac95d3b69adfa1676eb9c8eae6835d4f1671; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae; patch: 5.10.261; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <bbae351c0f32f7c200249e4aa6561b2b419dcf69; patch: 6.18.39; 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf <f0d88a4cd03affff6c08adf6c63964e235aede43; patch: 5.15.212; patch: 6.6.145

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

Patchlage reports hits and suspected hits. About everything else this system says nothing — neither this page nor the situation report ever claims that an estate is safe.