Overview
This blog post dissects a significant security vulnerability identified in the Linux kernel, specifically impacting the RDMA/Core subsystem. CVE-2025-22085, as it is officially known, has the potential to inflict serious damage on affected systems, leading to potential system compromise or data leakage. This vulnerability matters greatly due to the widespread use of Linux in servers, embedded systems, and many other areas, meaning a large number of devices and systems could potentially be at risk.
Vulnerability Summary
CVE ID: CVE-2025-22085
Severity: High (7.8 CVSS Severity Score)
Attack Vector: Network
Privileges Required: Low
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Linux Kernel | 6.14.0-rc4 and earlier versions
How the Exploit Works
The vulnerability resides in the RDMA/Core subsystem of the Linux kernel. It is a use-after-free vulnerability that occurs when renaming the device name. A use-after-free error can occur when a pointer to a resource is used after it has been freed, leading to various adverse effects such as system crashes, data corruption, and, in some cases, arbitrary code execution.
The issue was first reported by Syzbot, a software testing toolset developed by Google. It identified a slab-use-after-free condition in the nla_put function in the lib/nlattr.c file of the Linux kernel, which was triggered by a specific sequence of system calls.
Conceptual Example Code
While the specific exploit code for this vulnerability is not publicly available, the nature of use-after-free vulnerabilities means the exploit could conceptually involve reusing a pointer to a network device after it has been freed. This could be executed by an attacker sending a carefully crafted packet sequence to the vulnerable device, triggering the use-after-free condition and potentially leading to arbitrary code execution.
// Conceptual pseudocode for triggering use-after-free condition
struct net_device *dev = alloc_netdev();
// The device is registered, allocated memory
register_netdev(dev);
// The device is unregistered, memory is freed
unregister_netdev(dev);
// The device is used after being freed, triggering the use-after-free
netdev_ops->ndo_start_xmit(dev);Mitigation and Recommendations
The most direct mitigation is to apply the patch provided by the vendor, which resolves the use-after-free condition by ensuring that the device’s memory is not accessed after being freed. If patching is not immediately possible, deploying a Web Application Firewall (WAF) or Intrusion Detection System (IDS) configured to detect and block malicious traffic that attempts to exploit this vulnerability can serve as a temporary measure.
It is always recommended to follow best practice security measures such as keeping systems and software up-to-date, limiting the attack surface by disabling or uninstalling unnecessary services, and monitoring systems for unusual activity.