Overview
The CVE-2025-37838 vulnerability is a critical issue found in the Linux kernel’s ssi_protocol driver. Unpatched systems are exposed to potential system compromise or data leakage, making it a high-priority concern for all Linux users. The vulnerability arises from a use after free condition caused by a race condition in the ssi_protocol driver. In the hands of a skilled attacker, this vulnerability can be exploited to gain unauthorized access to sensitive data or even take over the system.
Vulnerability Summary
CVE ID: CVE-2025-37838
Severity: High (7.8/10)
Attack Vector: Local
Privileges Required: Low
User Interaction: None
Impact: Potential system compromise or data leakage
Affected Products
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Product | Affected Versions
Linux Kernel | 4.x, 5.x, 6.x
How the Exploit Works
The vulnerability lies in the ssi_protocol_probe() function. Here, &ssi->work is bound with ssip_xmit_work(), which allows the ssip_pn_xmit() function within the ssip_pn_ops structure to start the work. During the removal of the module, the ssi_protocol_remove() function initiates cleanup, which frees ssi via kfree(ssi). However, the previously mentioned work can still use the now-freed ssi, leading to a use after free bug.
Conceptual Example Code
Below is a conceptual example of how the vulnerability might be exploited. This is pseudocode and not meant to be implemented directly:
// Load module
load_module("vulnerable_module");
// Start the work in the background
start_work(ssi);
// Unload the module - this causes ssi to be freed
unload_module("vulnerable_module");
// The work continues in the background, unaware that ssi has been freed
// This causes a use-after-free vulnerability
continue_work(ssi);Mitigation
Users are strongly advised to apply the vendor patch as soon as it becomes available. In the interim, employing a Web Application Firewall (WAF) or Intrusion Detection System (IDS) may serve as a temporary mitigation strategy. However, it should be noted that these are only stopgap measures and do not address the root cause of the vulnerability.
Regularly updating your system and ensuring your security measures are up-to-date are crucial steps in mitigating the risk of such cybersecurity threats. It is always recommended to follow best security practices and maintain a proactive approach to system security.