Use of uninitialized resource in Linux kernel - CVE-2026-53218
Published: June 26, 2026
Vulnerability identifier: #VU135564
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-53218
CWE-ID: CWE-908
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: Linux Foundation
Affected software:
Linux kernel
Linux kernel
Detailed vulnerability description
The vulnerability allows a local user to disclose sensitive information.
The vulnerability exists due to an uninitialized memory exposure in nft_exthdr_init and the nft_exthdr evaluation paths when processing a userspace request with the NFT_EXTHDR_F_PRESENT flag set and an invalid length value. A local user can supply a crafted netfilter expression that causes uninitialized stack data from nft_regs to be retained in registers and disclose sensitive information.
The issue occurs because the initialized register bitmap can mark more bytes as written than the evaluation paths actually store when the presence flag is used.
How to mitigate CVE-2026-53218
Install security update from vendor's repository.
Sources
- https://git.kernel.org/stable/c/19748967d59c31d24d21d40b728570788310b237
- https://git.kernel.org/stable/c/46fc15a044e9938e7ea77786fb37edd2cd74f031
- https://git.kernel.org/stable/c/67b27434c43b68a97becda98c9f0c8cf6cba2134
- https://git.kernel.org/stable/c/772cecf198da732faebb5dcfc46d66a505be8495
- https://git.kernel.org/stable/c/78069a6d8bc86c9e036eb82c2af4a19cc1871a53
- https://git.kernel.org/stable/c/8738b1b6d0e639ca1fc0f61516afd3557ac4ecc6
- https://git.kernel.org/stable/c/cd513e43b4b2bd1de39e2367bc4261c699a8652f
- https://git.kernel.org/stable/c/f08fb3d42fd3aad0b7a263da3ac3ebaf0845e265