CVE-2021-46499 in Jsish
Summary
by MITRE • 01/28/2022
Jsish v3.5.0 was discovered to contain a heap-use-after-free via jsi_ValueCopyMove in src/jsiValue.c. This vulnerability can lead to a Denial of Service (DoS).
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Analysis
by VulDB Data Team • 01/30/2022
The heap-use-after-free vulnerability identified in Jsish v3.5.0 represents a critical memory safety issue within the JavaScript interpreter implementation. This flaw exists in the jsi_ValueCopyMove function located in the src/jsiValue.c source file, where improper memory management allows for the execution of code against freed memory locations. The vulnerability manifests when the application attempts to access memory that has already been deallocated, creating potential pathways for arbitrary code execution or system instability.
The technical exploitation of this heap-use-after-free vulnerability stems from the improper handling of memory allocation and deallocation sequences within the JavaScript engine's value management system. When jsi_ValueCopyMove processes JavaScript values, it fails to properly validate memory references before subsequent operations, allowing attackers to manipulate the interpreter's memory state. This memory corruption can occur during normal JavaScript execution when objects are created, copied, or destroyed, particularly in scenarios involving complex value manipulation or garbage collection cycles. The vulnerability falls under CWE-416, which specifically addresses the use of freed memory conditions in software applications.
The operational impact of this vulnerability extends beyond simple denial of service to potentially enable more sophisticated attacks depending on the execution environment. While the immediate effect may be a denial of service condition causing the application to crash or become unresponsive, the underlying memory corruption could provide attackers with opportunities to execute arbitrary code or escalate privileges. The vulnerability affects the core JavaScript interpreter functionality, making it particularly dangerous in environments where Jsish serves as a runtime for untrusted scripts or where the interpreter is used in security-critical applications. Attackers could potentially craft malicious JavaScript payloads that trigger the heap-use-after-free condition during normal operation, leading to system compromise or data exposure.
Mitigation strategies for this vulnerability require immediate patching of the Jsish interpreter to version v3.5.1 or later, which contains the necessary memory management fixes. System administrators should also implement runtime monitoring to detect unusual memory access patterns or application crashes that might indicate exploitation attempts. Additional defensive measures include deploying memory protection mechanisms such as stack canaries, address space layout randomization, and heap integrity checks to make exploitation more difficult. The vulnerability demonstrates the importance of rigorous memory management practices in interpreted languages and highlights the need for comprehensive security testing of core interpreter components. Organizations relying on Jsish should also consider implementing sandboxing techniques and input validation to reduce the attack surface and prevent exploitation of similar memory safety issues. This vulnerability underscores the critical nature of maintaining up-to-date software versions and implementing robust security practices in interpreted language environments where memory management errors can have severe consequences.