Quick answers
- Is This vulnerability exploited in the wild?
- No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.
- How severe is This vulnerability?
- Medium severity, with a CVSS score of 4, published 15 September 2025.
- Which products and versions are affected?
- express-xss-sanitizer (npm) SEMVER:introduced=0,last_affected=2.0.0.
- Is there a fix for This vulnerability?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is This vulnerability attacked?
- It is attacked over the network, in a software library.
- Am I affected?
- Check whether you run express-xss-sanitizer (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
The vulnerability is an unbounded recursion flaw (CWE-674) in the sanitize function (lib/sanitize.js) of express-xss-sanitizer when processing JSON request bodies. A remote, unauthenticated attacker can send a deeply nested payload to any endpoint protected by this sanitizer, causing the Node.js process to exceed its call stack limit with the error "Maximum call stack size exceeded," leading to a denial of service. The issue affects all versions through 2.0.0; no patch has been released as of the advisory date.
Affected products
- Ahmed Adel Fahim express-xss-sanitizer through 2.0.0
Timeline
- 2025-09-15: disclosed
- 2025-09-26: other: Advisory withdrawn as duplicate of GHSA-hvq2-wf92-j4f3