CVE-2025-37773 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
virtiofs: add filesystem context source name check
In certain scenarios, for example, during fuzz testing, the source name may be NULL, which could lead to a kernel panic. Therefore, an extra check for the source name should be added.
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Analysis
by VulDB Data Team • 03/16/2026
The vulnerability identified as CVE-2025-37773 resides within the Linux kernel's virtiofs implementation, specifically addressing a critical flaw in filesystem context handling. This issue manifests when the virtiofs driver processes filesystem contexts where the source name parameter may unexpectedly be NULL during operation. The vulnerability represents a classic null pointer dereference scenario that can lead to system instability and potential denial of service conditions. The flaw was discovered through fuzz testing methodologies which systematically probe system components for edge case behaviors and memory corruption vulnerabilities.
The technical implementation of this vulnerability stems from insufficient input validation within the virtiofs subsystem. When the kernel attempts to process filesystem contexts, it expects a valid source name parameter to properly initialize and manage filesystem operations. However, under certain conditions including fuzz testing scenarios, this parameter can be NULL, causing the kernel to attempt operations on invalid memory references. This type of vulnerability falls under CWE-476 which specifically addresses null pointer dereference conditions in software implementations. The absence of proper validation checks means that the kernel's virtiofs driver lacks the defensive programming practices necessary to handle malformed input gracefully.
Operationally, this vulnerability poses significant risks to systems utilizing virtiofs for virtualized filesystem operations, particularly in cloud computing environments and containerized applications where virtiofs is commonly employed for efficient file sharing between host and guest operating systems. A successful exploitation of this vulnerability could result in immediate kernel panics, system crashes, and complete service disruption. The impact extends beyond simple denial of service as such kernel-level flaws can potentially provide attackers with opportunities to escalate privileges or bypass security controls, making this vulnerability particularly concerning for production environments. The vulnerability affects systems running Linux kernels that implement the virtiofs driver, which is commonly found in virtualization platforms including KVM/QEMU environments and various cloud infrastructure deployments.
Mitigation strategies for CVE-2025-37773 should focus on implementing immediate code-level fixes that add proper null checks for the source name parameter before any operations are performed. The recommended approach involves adding defensive programming measures that validate input parameters early in the function execution flow, ensuring that NULL values are properly handled before they can cause kernel panics. System administrators should prioritize updating to patched kernel versions that include the necessary source name validation checks. Additionally, monitoring systems should be enhanced to detect anomalous virtiofs operations that might indicate exploitation attempts. Organizations utilizing virtualized environments should consider implementing runtime protections and input sanitization measures that can detect and prevent malformed filesystem context parameters from reaching the vulnerable kernel code paths. The fix aligns with ATT&CK technique T1059.003 which involves the exploitation of kernel vulnerabilities to gain system-level access and control.