CVE-2026-23326xsk: Fix fragment node deletion to prevent buffer leak

Official description

In the Linux kernel, the following vulnerability has been resolved: xsk: Fix fragment node deletion to prevent buffer leak After commit b692bf9a7543 ("xsk: Get rid of xdp_buff_xsk::xskb_list_node"), the list_node field is reused for both the xskb pool list and the buffer free list, this causes a buffer leak as described below. xp_free() checks if a buffer is already on the free list using list_empty(&xskb->list_node). When list_del() is used to remove a node from the xskb pool list, it doesn't reinitialize the node pointers. This means list_empty() will return false even after the node has been removed, causing xp_free() to incorrectly skip adding the buffer to the free list. Fix this by using list_del_init() instead of list_del() in all fragment handling paths, this ensures the list node is reinitialized after removal, allowing the list_empty() to work correctly.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/5172adf9efb8298a52f4dcdc3f98d4d9d1e06a6d
• https://git.kernel.org/stable/c/2a9ea988465ece5b6896b1bdc144170a64e84c35
• https://git.kernel.org/stable/c/645c6d8376ad4913cbffe0e0c2cca0c4febbe596
• https://git.kernel.org/stable/c/b38cbd4af5034635cff109e08788c63f956f3a69
• https://git.kernel.org/stable/c/60abb0ac11dccd6b98fd9182bc5f85b621688861