A crafted JavaScript input can trigger an internal assertion failure in QuickJS release 2025-09-13, fixed in commit 1dbba8a88eaa40d15a8a9b70bb1a0b8fb5b552e6 (2025-12-11), in file gc_decref_child in quickjs.c, when executed with the qjs interpreter using the -m option. This leads to an abort (SIGABRT) during garbage collection and causes a denial-of-service.
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.