CVE-2025-69653 is a vulnerability discovered in the QuickJS JavaScript engine, specifically in the release dated 2025-09-13. The flaw resides in the garbage collection subsystem, within the function gc_decref_child in the quickjs.c source file. When the QuickJS interpreter is executed with the -m option, a specially crafted JavaScript input can trigger an internal assertion failure. This assertion failure causes the interpreter process to abort by raising a SIGABRT signal during garbage collection. The root cause is an unchecked condition in the decrement reference logic for child objects, which leads to an invalid state and triggers the assertion. This vulnerability results in a denial-of-service (DoS) condition, as the interpreter crashes and cannot continue processing scripts. The issue was addressed and fixed in a commit dated 2025-12-11 (commit hash 1dbba8a88eaa40d15a8a9b70bb1a0b8fb5b552e6). No CVSS score has been assigned yet, and no public exploits have been reported. The vulnerability affects any environment using the vulnerable QuickJS interpreter version with the -m option enabled, which is often used for module execution. QuickJS is widely used in embedded systems, IoT devices, and lightweight JavaScript execution contexts, making this vulnerability relevant for those deployments.

The primary impact of CVE-2025-69653 is denial-of-service, where an attacker can cause the QuickJS interpreter to abort unexpectedly by supplying crafted JavaScript input. This can disrupt services or applications relying on QuickJS for script execution, potentially causing downtime or degraded functionality. Since QuickJS is often embedded in IoT devices, edge computing platforms, and lightweight runtime environments, this vulnerability could affect a broad range of devices and applications. The denial-of-service could be exploited remotely if the interpreter processes untrusted input, leading to service interruptions. While it does not directly compromise confidentiality or integrity, the availability impact can be significant, especially in critical systems or automated environments where QuickJS is embedded. The lack of authentication or user interaction requirements increases the risk of exploitation in exposed environments. Organizations using QuickJS in production or embedded contexts should consider this vulnerability a high priority to address.

To mitigate CVE-2025-69653, organizations should immediately update to the patched QuickJS version that includes the fix committed on 2025-12-11 (commit 1dbba8a88eaa40d15a8a9b70bb1a0b8fb5b552e6). If upgrading is not immediately feasible, consider disabling or restricting the use of the -m option in the QuickJS interpreter to prevent triggering the vulnerable code path. Implement input validation and sanitization on any JavaScript inputs processed by QuickJS to reduce the risk of malicious payloads causing crashes. For embedded or IoT devices, ensure firmware updates include the patched QuickJS version and verify that update mechanisms are secure and reliable. Monitor logs and application behavior for unexpected interpreter crashes that may indicate attempted exploitation. Additionally, isolate QuickJS execution environments to limit the impact of potential denial-of-service conditions. Finally, maintain awareness of vendor advisories and community updates regarding QuickJS vulnerabilities and patches.