### Summary 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). ### Details When the `comma` option is set to `true` (not the default, but configurable in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `['a', 'b', 'c']`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of arbitrarily large arrays from a single parameter, leading to excessive memory allocation. **Vulnerable code** (lib/parse.js: lines ~40-50): ```js if (val && typeof val === 'string' && options.comma && val.indexOf(',') > -1) { return val.split(','); } if (options.throwOnLimitExceeded && currentArrayLength >= options.arrayLimit) { throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + ' element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.'); } return val; ``` The `split(',')` returns the array immediately, skipping the subsequent limit check. Downstream merging via `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`), allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`, which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in v6.14.1 per GHSA-6rw7-vpxm-498p). ### PoC **Test 1 - Basic bypass:** ``` npm install qs ``` ```js const qs = require('qs'); const payload = 'a=' + ','.repeat(25); // 26 elements after split (bypasses arrayLimit: 5) const options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true }; try { const result = qs.parse(payload, options); console.log(result.a.length); // Outputs: 26 (bypass successful) } catch (e) { console.log('Limit enforced:', e.message); // Not thrown } ``` **Configuration:** - `comma: true` - `arrayLimit: 5` - `throwOnLimitExceeded: true` Expected: Throws "Array limit exceeded" error. Actual: Parses successfully, creating an array of length 26. ### Impact Denial of Service (DoS) via memory exhaustion.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - ### Summary 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). ### Details When the `comma` option is set to `true` (not the default, but configurable
    in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `['a',
    'b', 'c']`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded
    occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of
    arbitrarily large arrays from a single parameter, leading to excessive memory allocation. **Vulnerable
    code** (lib/parse.js: lines ~40-50): ```js if (val && typeof val === 'string' && options.comma &&
    val.indexOf(',') > -1) { return val.split(','); } if (options.throwOnLimitExceeded && currentArrayLength
    >= options.arrayLimit) { throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + '
    element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.'); } return val; ``` The
    `split(',')` returns the array immediately, skipping the subsequent limit check. Downstream merging via
    `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy
    allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`),
    allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`,
    which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in
    v6.14.1 per GHSA-6rw7-vpxm-498p). ### PoC **Test 1 - Basic bypass:** ``` npm install qs ``` ```js const qs
    = require('qs'); const payload = 'a=' + ','.repeat(25); // 26 elements after split (bypasses arrayLimit:
    5) const options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true }; try { const result =
    qs.parse(payload, options); console.log(result.a.length); // Outputs: 26 (bypass successful) } catch (e) {
    console.log('Limit enforced:', e.message); // Not thrown } ``` **Configuration:** - `comma: true` -
    `arrayLimit: 5` - `throwOnLimitExceeded: true` Expected: Throws "Array limit exceeded" error. Actual:
    Parses successfully, creating an array of length 26. ### Impact Denial of Service (DoS) via memory
    exhaustion. (CVE-2026-2391)

The remote Fedora 42 host has a package installed that is affected by multiple vulnerabilities as referenced in the FEDORA-2026-ca43aa006f advisory.

    33.0.1 release

Tenable has extracted the preceding description block directly from the Fedora security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - ### Summary 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). ### Details When the `comma` option is set to `true` (not the default, but configurable     in applications), qs allows parsing comma-separated strings as arrays (e.g., `?param=a,b,c` becomes `['a',     'b', 'c']`). However, the limit check for `arrayLimit` (default: 20) and the optional throwOnLimitExceeded     occur after the comma-handling logic in `parseArrayValue`, enabling a bypass. This permits creation of     arbitrarily large arrays from a single parameter, leading to excessive memory allocation. **Vulnerable     code** (lib/parse.js: lines ~40-50): ```js if (val && typeof val === 'string' && options.comma &&     val.indexOf(',') > -1) { return val.split(','); } if (options.throwOnLimitExceeded && currentArrayLength     >= options.arrayLimit) { throw new RangeError('Array limit exceeded. Only ' + options.arrayLimit + '     element' + (options.arrayLimit === 1 ? '' : 's') + ' allowed in an array.'); } return val; ``` The     `split(',')` returns the array immediately, skipping the subsequent limit check. Downstream merging via     `utils.combine` does not prevent allocation, even if it marks overflows for sparse arrays.This discrepancy     allows attackers to send a single parameter with millions of commas (e.g., `?param=,,,,,,,,...`),     allocating massive arrays in memory without triggering limits. It bypasses the intent of `arrayLimit`,     which is enforced correctly for indexed (`a[0]=`) and bracket (`a[]=`) notations (the latter fixed in     v6.14.1 per GHSA-6rw7-vpxm-498p). ### PoC **Test 1 - Basic bypass:** ``` npm install qs ``` ```js const qs     = require('qs'); const payload = 'a=' + ','.repeat(25); // 26 elements after split (bypasses arrayLimit:
    5) const options = { comma: true, arrayLimit: 5, throwOnLimitExceeded: true }; try { const result =     qs.parse(payload, options); console.log(result.a.length); // Outputs: 26 (bypass successful) } catch (e) {     console.log('Limit enforced:', e.message); // Not thrown } ``` **Configuration:** - `comma: true` -     `arrayLimit: 5` - `throwOnLimitExceeded: true` Expected: Throws Array limit exceeded error. Actual:
    Parses successfully, creating an array of length 26. ### Impact Denial of Service (DoS) via memory     exhaustion. (CVE-2026-2391)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
462259	Echo: qs: security update to 6.14.2	Tenable Cloud Security	Echo Local Security Checks	Local	medium
462259	Echo: qs: security update to 6.14.2	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	medium
305115	Fedora 42 : nextcloud (2026-ca43aa006f)	Nessus	Fedora Local Security Checks	Local	high
298899	Linux Distros Unpatched Vulnerability : CVE-2026-2391	Nessus	Misc.	Local	medium
437712	SCA: security update for qs (GHSA-w7fw-mjwx-w883)	Tenable Cloud Security	SCA Checks	Local	medium
437712	SCA: security update for qs (GHSA-w7fw-mjwx-w883)	Tenable Self-Hosted Container Security	SCA Checks	Local	medium

Detections

Analytics

CVE-2026-2391

medium

Tenable Plugins

medium

medium

high

medium

medium

medium