NULL Pointer Dereference Affecting qs package, versions >=6.11.1 <6.15.2
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-JS-QS-16721866
- published17 May 2026
- disclosed17 May 2026
- creditJoanna Lange
Introduced: 17 May 2026
CVE-2026-8723 (opens in a new tab)How to fix?
Upgrade qs to version 6.15.2 or higher.
Overview
qs is a querystring parser that supports nesting and arrays, with a depth limit.
Affected versions of this package are vulnerable to NULL Pointer Dereference in the stringify() function, when processing arrays with the options arrayFormat: 'comma' and encodeValuesOnly: true that contain null or undefined elements. An attacker can cause errors by supplying mailcious input that results in these options being used with arrays containing null or undefined values. This only causes a crash if application code makes calls outside a request-handler error boundary (background jobs, startup paths, stream pipelines) or explicitly disables framework error handling.
PoC
const qs = require('qs');
qs.stringify({ a: [null, 'b'] }, { arrayFormat: 'comma', encodeValuesOnly: true });
qs.stringify({ a: [undefined, 'b'] }, { arrayFormat: 'comma', encodeValuesOnly: true });
qs.stringify({ a: [null] }, { arrayFormat: 'comma', encodeValuesOnly: true });