Introduction
Privilege escalation on production Linux servers can undermine network segmentation and allow attackers to move laterally with ease. CVE-2025-21086, disclosed in August 2025, targets the Linux kernel-mode drivers for Intel 700 Series Ethernet controllers, which are widely deployed in enterprise and data center environments. The vulnerability arises from improper input validation, giving authenticated local users a path to escalate privileges if the system is running a vulnerable driver version.
Intel is a global leader in networking and compute hardware. Its Ethernet controllers, including the 700 Series, are embedded in countless servers and appliances powering cloud, enterprise, and critical infrastructure. The security of these drivers is crucial for organizations relying on Intel hardware for reliable and secure networking.
Technical Information
CVE-2025-21086 is rooted in improper input validation within the Linux kernel-mode driver for Intel 700 Series Ethernet controllers. Specifically, driver versions prior to 2.28.5 do not adequately check or sanitize user-supplied input before processing it in privileged code paths. This flaw is classified under CWE-20: Improper Input Validation.
An authenticated user with local access can craft input that triggers the vulnerable code path. Because the driver operates in kernel mode, successful exploitation allows the attacker to execute operations with elevated privileges, potentially compromising the entire system. The attack complexity is rated as high, requiring detailed knowledge of the driver internals and system configuration. No public code snippets or proof-of-concept exploits are available as of this writing.
Affected drivers are those for Intel 700 Series Ethernet controllers (such as I710, X710, XL710, XXV710) running on Linux, with versions earlier than 2.28.5. The vulnerability does not affect Windows drivers or Linux driver versions 2.28.5 and later.
Patch Information
Intel has released version 2.28.5 of the Intel 700 Series Ethernet Linux driver to address CVE-2025-21086 and related vulnerabilities. All users and organizations running affected hardware should update to version 2.28.5 or later as soon as possible. The fixed drivers are available from Intel's official GitHub repository:
https://github.com/intel/ethernet-linux-i40e/releases
For further details and official advisory information, refer to:
https://www.intel.com/content/www/us/en/security-center/advisory/intel-sa-01335.html
Affected Systems and Versions
- Intel 700 Series Ethernet controllers (including I710, X710, XL710, XXV710)
- Linux kernel-mode drivers for these controllers
- Vulnerable driver versions: all versions prior to 2.28.5
- Systems running driver version 2.28.5 or later are not affected
- Windows drivers are not affected
Vendor Security History
Intel has previously addressed privilege escalation vulnerabilities in its Ethernet drivers, such as those documented in INTEL-SA-00554 and INTEL-SA-00255. Intel typically coordinates public disclosure with patch availability, and its advisories are detailed and actionable. However, the recurrence of input validation issues in privileged drivers indicates ongoing challenges in secure driver development for complex hardware.