Bug 2451215 (CVE-2026-23326)

Summary: CVE-2026-23326 kernel: xsk: Fix fragment node deletion to prevent buffer leak
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
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Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in the Linux kernel. An issue in the eXpress Data Path (XDP) socket (xsk) component, specifically during fragment node deletion, can lead to a buffer leak. This occurs because a list node is not properly reinitialized after removal, causing the system to incorrectly manage memory. This could potentially lead to system instability or a denial of service.
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Description OSIDB Bzimport 2026-03-25 11:05:10 UTC
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.