The arrayLimit option in qs does not enforce limits for comma-separated values when comma: true is enabled, allowing attackers to cause denial-of-service via memory exhaustion. This is a bypass of the array limit enforcement, similar to the bracket notation bypass addressed in GHSA-6rw7-vpxm-498p (CVE-2025-15284).
The arrayLimit option in qs did not enforce limits for bracket notation (a[]=1&a[]=2), only for indexed notation (a[0]=1). This is a consistency bug; arrayLimit should apply uniformly across all array notations. Note: The default parameterLimit of 1000 effectively mitigates the DoS scenario originally described. With default options, bracket notation cannot produce arrays larger than parameterLimit regardless of arrayLimit, because each a[]=value consumes one parameter slot. The severity has been reduced …
qs before 6.10.3 allows attackers to cause a Node process hang because an __ proto__ key can be used. In many typical web framework use cases, an unauthenticated remote attacker can place the attack payload in the query string of the URL that is used to visit the application, such as a[proto]=b&a[proto]&a[length]=100000000. The fix was backported to qs 6.9.7, 6.8.3, 6.7.3, 6.6.1, 6.5.3, 6.4.1, 6.3.3, and 6.2.4.
This advisory has been invalidated due to the CVE being rejected.
The qs module before 1.0.0 does not have an option or default for specifying object depth and when parsing a string representing a deeply nested object will block the event loop for long periods of time. An attacker could leverage this to cause a temporary denial-of-service condition, for example, in a web application, other requests would not be processed while this blocking is occurring.
The qs module before 1.0.0 in Node.js does not call the compact function for array data, which allows remote attackers to cause a denial of service (memory consumption) by using a large index value to create a sparse array.
The qs module is vulnerable to a DoS. A malicious user can send an evil request to cause the web framework crash.
qs is affected by a denial of service vulnerability that results from excessive recursion in parsing a deeply nested JSON string.