Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 6.18.16/6.19.6/7.0-rc2. Affected by this vulnerability is the function xp_free of the component xsk. The manipulation results in initialization. This vulnerability is cataloged as CVE-2026-23326. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 6.18.16/6.19.6/7.0-rc2. Affected is the function xp_free of the component xsk. The manipulation with an unknown input leads to a initialization vulnerability. CWE is classifying the issue as CWE-665. The product does not initialize or incorrectly initializes a resource, which might leave the resource in an unexpected state when it is accessed or used. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

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.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-23326 since 01/13/2026. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 03/30/2026).

The vulnerability scanner Nessus provides a plugin with the ID 303743 (Linux Distros Unpatched Vulnerability : CVE-2026-23326), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.18.17, 6.19.7 or 7.0-rc3 eliminates this vulnerability. Applying the patch 5172adf9efb8298a52f4dcdc3f98d4d9d1e06a6d/2a9ea988465ece5b6896b1bdc144170a64e84c35/645c6d8376ad4913cbffe0e0c2cca0c4febbe596/b38cbd4af5034635cff109e08788c63f956f3a69/60abb0ac11dccd6b98fd9182bc5f85b621688861 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (303743) and CERT Bund (WID-SEC-2026-0861). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

• Open Source Linux Kernel

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.19.0
• 6.19.1
• 6.19.2
• 6.19.3
• 6.19.4
• 6.19.5
• 6.19.6
• 7.0-rc1
• 7.0-rc2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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