CVE-2025-38377 Information

Jul 26, 2025 cve

Description

In the Linux kernel the following vulnerability has been resolved:

rose: fix dangling neighbour pointers in rose_rt_device_down()

There are two bugs in rose_rt_device_down() that can cause use-after-free:

  1. The loop bound t->count is modified within the loop which can cause the loop to terminate early and miss some entries.

  2. When removing an entry from the neighbour array the subsequent entries are moved up to fill the gap but the loop index i is still incremented causing the next entry to be skipped.

For example if a node has three neighbours (A A B) with count=3 and A is being removed the second A is not checked.

i=0: (A A B) -> (A B) with count=2
      ^ checked
i=1: (A B)    -> (A B) with count=2
         ^ checked (B not A!)
i=2: (doesn't occur because i < count is false)

This leaves the second A in the array with count=2 but the rose_neigh structure has been freed. Code that accesses these entries assumes that the first count entries are valid pointers causing a use-after-free when it accesses the dangling pointer.

Fix both issues by iterating over the array in reverse order with a fixed loop bound. This ensures that all entries are examined and that the removal of an entry doesn’t affect subsequent iterations.

Reference

https://git.kernel.org/stable/c/2b952dbb32fef835756f07ff0cd77efbb836dfea https://git.kernel.org/stable/c/2c6c82ee074bfcfd1bc978ec45bfea37703d840a https://git.kernel.org/stable/c/34a500caf48c47d5171f4aa1f237da39b07c6157 https://git.kernel.org/stable/c/446ac00b86be1670838e513b643933d78837d8db https://git.kernel.org/stable/c/7a1841c9609377e989ec41c16551309ce79c39e4 https://git.kernel.org/stable/c/94e0918e39039c47ddceb609500817f7266be756 https://git.kernel.org/stable/c/b6b232e16e08c6dc120672b4753392df0d28c1b4 https://git.kernel.org/stable/c/fe62a35fb1f77f494ed534fc69a9043dc5a30ce1

CNNVD-202507-3203 (Published: 2025-07-25)

Share on: