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CVE-2026-64422

net: ipv4: bound TCP reordering sysctl writes and MTU probe sizes

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.10.261, 5.15.212, 6.1.178, 6.6.145, 6.12.96, and 2 more
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: no
  • Technical impact: partial

Summary

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.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: no · Technical impact: partial

  3. Record last updated

Affected versions

  • Linux Linux

    From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in f0d88a4cd03affff6c08adf6c63964e235aede43; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in 27ddf4486c7dbf5bdd393fa8bef6b67179796d98; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in 782708ca1ea1f68b8cbb5ea3a7f5f18d0000efae; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in e81f805824a8109504fce090641b17d135b48cd1; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in 99206ce2244f8a3ed64298d0667c9055845a5dc7; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in bbae351c0f32f7c200249e4aa6561b2b419dcf69; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in a094ac95d3b69adfa1676eb9c8eae6835d4f1671; From 91cc17c0e5e5ada156a8d5787a2509d263ea6bbf · fixed in efb8763d7bbb40cff4cc55a6b62c3095a038149c

  • Linux Linux

    2.6.24

  • KernelLinux

    From 2.6.24 · fixed in 5.10.261; From 5.11.0 · fixed in 5.15.212; From 5.16.0 · fixed in 6.1.178; From 6.2.0 · fixed in 6.6.145; From 6.7.0 · fixed in 6.12.96; From 6.13.0 · fixed in 6.18.39; From 6.19.0 · fixed in 7.1.4

References 8

git.kernel.org