CVE-2019-20795 in iproute2
Summary
by MITRE
iproute2 before 5.1.0 has a use-after-free in get_netnsid_from_name in ip/ipnetns.c.
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Analysis
by VulDB Data Team • 03/05/2025
The vulnerability identified as CVE-2019-20795 represents a critical use-after-free flaw within the iproute2 network management utilities suite, specifically affecting versions prior to 5.1.0. This issue resides in the get_netnsid_from_name function located within the ip/ipnetns.c source file, which is part of the broader iproute2 package used extensively for network configuration and management in linux environments. The iproute2 suite serves as a fundamental component for network administration tasks including routing, traffic control, and network namespace management, making this vulnerability particularly concerning for system security and stability.
The technical nature of this vulnerability stems from improper memory management within the network namespace identification process. When the get_netnsid_from_name function processes network namespace names to retrieve their corresponding identifiers, it fails to properly handle memory allocation and deallocation sequences. This flaw creates a scenario where a memory block is freed from the system but remains accessible to subsequent operations, allowing for potential arbitrary code execution or system instability. The use-after-free condition typically occurs when the application attempts to access memory that was previously deallocated, potentially leading to unpredictable behavior, crashes, or exploitation by malicious actors who could leverage this vulnerability to execute unauthorized commands.
The operational impact of CVE-2019-20795 extends beyond simple system instability to encompass potential privilege escalation and remote code execution capabilities. Network administrators and system operators who rely on iproute2 for network namespace management are particularly at risk, as this vulnerability could be exploited to gain unauthorized access to network configuration processes. The vulnerability's exploitation potential aligns with ATT&CK technique T1068 which covers 'Exploitation for Privilege Escalation' and CWE-416 which addresses 'Use After Free' conditions. Systems running affected versions of iproute2, particularly those with network namespace functionality enabled, face significant risk of compromise, as attackers could potentially manipulate network namespace operations to execute malicious code with elevated privileges.
Mitigation strategies for this vulnerability center around immediate version updates to iproute2 5.1.0 or later, which contain the necessary memory management fixes to prevent the use-after-free condition. Organizations should prioritize patching systems that utilize iproute2 for network namespace operations, particularly those with network administration capabilities or remote access. Additional protective measures include implementing network segmentation to limit access to systems running iproute2, monitoring for unusual network namespace operations, and conducting thorough vulnerability assessments of network management tools. The fix implemented in version 5.1.0 typically involves proper memory handling procedures that ensure allocated memory blocks are not accessed after deallocation, thereby eliminating the conditions that enable exploitation of this use-after-free vulnerability.