@asymmetric-effort/nogginlessdom ReDoS via unvalidated regex in HTMLInputElement

Severity: medium · CVSS 4 · Published 2026-07-02

@asymmetric-effort/nogginlessdom is a JavaScript library that provides DOM element validation. The library's HTMLInputElement.checkValidity() method constructs regular expressions directly from user-controlled input patterns without sanitization, allowing an attacker to craft malicious regex patterns that cause catastrophic backtracking and freeze the application's event loop, resulting in a denial of service.

Vendors: Asymmetric Effort, npm.

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 2 July 2026.
Which products and versions are affected?
Asymmetric Effort Nogginlessdom <= 0.0.21; @asymmetric-effort/nogginlessdom (npm) SEMVER:introduced=0,fixed=0.0.22.
Is there a fix for This vulnerability?
Yes. @asymmetric-effort/nogginlessdom (npm): upgrade to 0.0.22 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is This vulnerability attacked?
It is attacked over the network, in a software library.
Am I affected?
Check whether you run Asymmetric Effort Nogginlessdom or @asymmetric-effort/nogginlessdom (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.

How to fix

  • @asymmetric-effort/nogginlessdom (npm): upgrade to 0.0.22 or later
    npm install @asymmetric-effort/nogginlessdom@0.0.22

Technical details

This is a Regular Expression Denial of Service (ReDoS) vulnerability in the HTMLInputElement.checkValidity() method. The vulnerable component directly constructs a RegExp object from the user-controlled pattern property without sanitization or timeout protection, enabling an attacker to inject patterns with nested quantifiers (e.g., (a+)+) that trigger exponential backtracking. The attack requires no authentication or special privileges; any caller of checkValidity() with an attacker-controlled pattern can exploit this. A successful exploit freezes the event loop, causing the application to become unresponsive. The vulnerability was patched in version 0.0.22 by adding a 1024-character pattern length limit and nested quantifier detection that rejects dangerous patterns before regex compilation.

Affected products

  • asymmetric-effort nogginlessdom <= 0.0.21

Timeline

  • 2026-07-02: disclosed: Advisory GHSA-x4hg-hfwf-p9mw published
  • 2026-07-02: patched: Fix released in version 0.0.22 with pattern length limit and nested quantifier detection

References

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.