CVE-2021-46496 in Jsish
Summary
by MITRE • 01/28/2022
Jsish v3.5.0 was discovered to contain a heap-use-after-free via Jsi_ObjFree in src/jsiObj.c. This vulnerability can lead to a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 01/30/2022
The vulnerability identified as CVE-2021-46496 affects Jsish version 3.5.0 and represents a critical heap-use-after-free condition within the Jsi_ObjFree function located in the src/jsiObj.c source file. This type of vulnerability occurs when a program continues to reference memory that has already been freed, creating potential pathways for malicious exploitation. The heap-use-after-free flaw specifically manifests during object cleanup operations where the Jsish interpreter fails to properly manage memory references, leading to unpredictable behavior and system instability.
The technical implementation of this vulnerability stems from improper memory management practices within the JavaScript interpreter's object handling mechanisms. When Jsi_ObjFree executes, it attempts to release memory associated with JavaScript objects, but the function does not adequately prevent subsequent access to freed memory locations. This memory corruption issue can be triggered through specific JavaScript code sequences that manipulate object references in ways that cause the interpreter to attempt to access already-released heap memory. The flaw operates at the intersection of memory management and object lifecycle handling, where the interpreter's garbage collection and object cleanup processes fail to maintain proper reference tracking.
From an operational impact perspective, this vulnerability creates significant risks for systems running Jsish v3.5.0, particularly those processing untrusted JavaScript input or serving web applications. The heap-use-after-free condition can result in immediate program termination, leading to denial of service conditions that disrupt legitimate user access to services. Attackers could potentially exploit this weakness by crafting malicious JavaScript code that triggers the specific memory access patterns causing the heap corruption, thereby enabling remote code execution or system compromise. The vulnerability's impact extends beyond simple service disruption as it represents a fundamental memory safety issue that undermines the interpreter's stability and security posture.
Security professionals should recognize this vulnerability as aligning with CWE-416, which specifically addresses use-after-free conditions in software implementations. The flaw also connects to broader ATT&CK techniques related to privilege escalation and denial of service operations, as adversaries may leverage heap corruption vulnerabilities to gain unauthorized access or disrupt system availability. Organizations utilizing Jsish should prioritize immediate mitigation through version updates to address the memory management issues present in v3.5.0, while also implementing runtime protections such as address space layout randomization and heap integrity checking mechanisms. Additionally, input validation and sandboxing measures should be strengthened to prevent exploitation attempts that could leverage this vulnerability for more severe security impacts.