CVE-2021-46498 in Jsish
Summary
by MITRE • 01/28/2022
Jsish v3.5.0 was discovered to contain a heap-use-after-free via jsi_wswebsocketObjFree in src/jsiWebSocket.c. This vulnerability can lead to a Denial of Service (DoS).
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 01/30/2022
The vulnerability identified as CVE-2021-46498 affects Jsish version 3.5.0, a JavaScript interpreter and runtime environment. This security flaw manifests as a heap-use-after-free condition within the jsi_wswebsocketObjFree function located in the src/jsiWebSocket.c source file. The heap-use-after-free vulnerability represents a critical memory safety issue that occurs when a program continues to access memory locations that have already been freed, potentially leading to unpredictable behavior and system instability. This particular vulnerability specifically impacts the WebSocket object management functionality within the Jsish interpreter, creating a scenario where memory corruption can occur during the cleanup process of WebSocket connections.
The technical exploitation of this vulnerability involves the improper handling of WebSocket object lifecycle management within the Jsish runtime environment. When the jsi_wswebsocketObjFree function executes, it attempts to free memory associated with WebSocket objects, but subsequent operations may still reference these already-released memory locations. This memory management error falls under the CWE-416 category of Use After Free, which is classified as a serious weakness in software security. The vulnerability's impact extends beyond simple memory corruption, as it can be leveraged to trigger a denial of service condition that effectively renders the affected system or application unavailable to legitimate users. The DoS condition occurs because the heap corruption can cause the interpreter to crash or enter an unstable state, preventing normal execution of JavaScript code that relies on WebSocket functionality.
From an operational perspective, this vulnerability presents significant risks to systems that depend on Jsish for WebSocket-based communication or server-side JavaScript execution. The DoS attack vector can be exploited by malicious actors who send specially crafted WebSocket messages or connection requests that trigger the memory corruption scenario during object cleanup. This makes the vulnerability particularly dangerous in production environments where continuous availability is critical. The attack surface expands when considering that WebSocket connections are commonly used in real-time applications, web servers, and networked systems where Jsish serves as the JavaScript runtime. Security researchers have documented similar patterns of heap-use-after-free vulnerabilities in other JavaScript engines and network libraries, where improper memory management during object destruction leads to system instability and potential privilege escalation scenarios.
Mitigation strategies for CVE-2021-46498 should prioritize immediate patching of the Jsish interpreter to version 3.5.1 or later, which contains the necessary memory management fixes for the WebSocket object cleanup process. Organizations should also implement network-level monitoring to detect anomalous WebSocket traffic patterns that might indicate exploitation attempts, as outlined in the ATT&CK framework's T1499.3 technique for network disruption. Additionally, runtime protections such as address space layout randomization and heap hardening techniques can provide additional defense-in-depth measures. System administrators should conduct comprehensive vulnerability assessments to identify all systems running affected Jsish versions and establish incident response procedures for potential exploitation attempts. The vulnerability demonstrates the importance of thorough memory management testing, particularly in network-facing applications that handle dynamic object creation and destruction, aligning with industry best practices for secure coding and the OWASP Top Ten security risks that emphasize injection flaws and memory safety issues in application development.