CVE-2019-12255 in VxWorks
Summary
by MITRE
Wind River VxWorks 6.5 through 6.9.3 has a Buffer Overflow in the TCP component (issue 1 of 4). This is a IPNET security vulnerability: TCP Urgent Pointer = 0 that leads to an integer underflow. Affected versions: 6.6, 6.7, 6.8, 6.9
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Analysis
by VulDB Data Team • 09/27/2025
The vulnerability identified as CVE-2019-12255 represents a critical buffer overflow condition within Wind River VxWorks operating systems versions 6.5 through 6.9.3, specifically affecting the TCP component of the IPNET security framework. This issue manifests when processing TCP urgent pointer fields set to zero, creating a scenario where integer underflow occurs within the network stack implementation. The vulnerability affects multiple versions including 6.6, 6.7, 6.8, and 6.9, while version 6.5 and 6.9.3 remain unaffected by this particular flaw. The root cause stems from inadequate input validation within the TCP protocol handling mechanism, where the system fails to properly validate the urgent pointer field value before performing arithmetic operations.
The technical exploitation of this vulnerability occurs when a malicious remote attacker sends specially crafted TCP packets containing an urgent pointer value of zero to a vulnerable VxWorks system. The system's TCP stack processes this malformed packet without proper boundary checking, leading to an integer underflow condition that can result in memory corruption. This memory corruption typically manifests as a buffer overflow within the TCP receive buffer or associated control structures, potentially allowing attackers to overwrite adjacent memory locations. The integer underflow specifically occurs when the system attempts to perform arithmetic operations on the urgent pointer value, which when set to zero, causes the calculation to wrap around to a large negative value, subsequently leading to improper buffer indexing.
The operational impact of this vulnerability extends beyond simple denial of service conditions, as it presents significant opportunities for remote code execution and system compromise. Attackers exploiting this vulnerability can potentially execute arbitrary code with the privileges of the affected process, typically running at kernel level within the VxWorks environment. This capability enables attackers to gain full control over the affected embedded system, potentially leading to complete system compromise. The vulnerability affects critical infrastructure systems that rely on VxWorks for real-time operations including industrial control systems, automotive applications, and network equipment where the compromised device could be used as a foothold for broader network infiltration. The impact is particularly severe in environments where VxWorks is deployed in safety-critical applications where system integrity and availability are paramount.
Mitigation strategies for this vulnerability should include immediate deployment of patches provided by Wind River, which address the integer underflow condition through proper input validation and boundary checking within the TCP component. Organizations should implement network segmentation and access control measures to limit exposure of vulnerable systems to untrusted networks. The mitigation process should also include monitoring network traffic for suspicious TCP packets with malformed urgent pointer fields and implementing intrusion detection systems that can identify exploitation attempts. Additionally, system administrators should conduct thorough vulnerability assessments to identify all instances of affected VxWorks versions within their infrastructure and prioritize remediation based on risk assessment. Security teams should also consider implementing network-based firewalls and access control lists that can filter out potentially malicious TCP packets before they reach vulnerable systems. This vulnerability aligns with CWE-129, which addresses improper validation of length of input buffers, and maps to ATT&CK technique T1210 for exploitation of remote services, highlighting the need for comprehensive network security controls and proper input validation mechanisms.