Linux Distros Unpatched Vulnerability : CVE-2026-2391

medium Nessus Plugin ID 298899

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

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.

Solution

There is no known solution at this time.

Plugin Details

Severity: Medium

ID: 298899

File Name: unpatched_CVE_2026_2391.nasl

Version: 1.3

Type: local

Agent: unix

Family: Misc.

Published: 2/13/2026

Updated: 2/26/2026

Supported Sensors: Agentless Assessment, Frictionless Assessment Agent, Frictionless Assessment AWS, Frictionless Assessment Azure, Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 7

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-2391

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 7.1

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:P/RL:U/RC:C

CVSS v4

Risk Factor: Medium

Base Score: 6.3

Threat Score: 2.9

Threat Vector: CVSS:4.0/E:P

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, p-cpe:/a:centos:centos:polkit-libs, p-cpe:/a:centos:centos:sgx-libs, p-cpe:/a:redhat:enterprise_linux:tdx-qgs, p-cpe:/a:centos:centos:firefox-x11, p-cpe:/a:centos:centos:grafana-prometheus, p-cpe:/a:redhat:enterprise_linux:pcs, p-cpe:/a:redhat:enterprise_linux:mozjs60, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:grafana-influxdb, p-cpe:/a:centos:centos:polkit-devel, p-cpe:/a:redhat:enterprise_linux:grafana-mssql, cpe:/o:redhat:enterprise_linux:10, cpe:/o:canonical:ubuntu_linux:14.04:-:lts, p-cpe:/a:redhat:enterprise_linux:grafana, p-cpe:/a:canonical:ubuntu_linux:node-qs, p-cpe:/a:centos:centos:polkit, p-cpe:/a:centos:centos:firefox, p-cpe:/a:redhat:enterprise_linux:firefox-x11, p-cpe:/a:centos:centos:grafana-stackdriver, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:redhat:enterprise_linux:7, p-cpe:/a:redhat:enterprise_linux:grafana-influxdb, p-cpe:/a:centos:centos:grafana-elasticsearch, p-cpe:/a:centos:centos:grafana-azure-monitor, p-cpe:/a:redhat:enterprise_linux:polkit-libs, p-cpe:/a:redhat:enterprise_linux:gjs, p-cpe:/a:centos:centos:grafana-opentsdb, p-cpe:/a:centos:centos:gjs, p-cpe:/a:redhat:enterprise_linux:polkit-docs, p-cpe:/a:centos:centos:sgx-mpa, p-cpe:/a:centos:centos:grafana, p-cpe:/a:debian:debian_linux:node-qs, p-cpe:/a:redhat:enterprise_linux:firefox, p-cpe:/a:redhat:enterprise_linux:grafana-stackdriver, p-cpe:/a:centos:centos:tdx-qgs, p-cpe:/a:redhat:enterprise_linux:grafana-azure-monitor, p-cpe:/a:centos:centos:grafana-cloudwatch, p-cpe:/a:redhat:enterprise_linux:grafana-opentsdb, p-cpe:/a:redhat:enterprise_linux:grafana-elasticsearch, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, p-cpe:/a:centos:centos:grafana-loki, p-cpe:/a:centos:centos:grafana-mysql, cpe:/o:redhat:enterprise_linux:8, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:redhat:enterprise_linux:grafana-loki, p-cpe:/a:centos:centos:mozjs60-devel, cpe:/o:centos:centos:7, p-cpe:/a:centos:centos:thunderbird, p-cpe:/a:redhat:enterprise_linux:pcs-snmp, cpe:/o:debian:debian_linux:12.0, p-cpe:/a:redhat:enterprise_linux:sgx-pckid-tool, cpe:/o:centos:centos:8, p-cpe:/a:centos:centos:grafana-selinux, p-cpe:/a:centos:centos:mozjs60, p-cpe:/a:redhat:enterprise_linux:sgx-libs, p-cpe:/a:redhat:enterprise_linux:polkit-devel, p-cpe:/a:redhat:enterprise_linux:grafana-postgres, p-cpe:/a:centos:centos:grafana-graphite, p-cpe:/a:redhat:enterprise_linux:grafana-prometheus, p-cpe:/a:redhat:enterprise_linux:thunderbird, p-cpe:/a:redhat:enterprise_linux:polkit, p-cpe:/a:redhat:enterprise_linux:mozjs60-devel, p-cpe:/a:centos:centos:pcs, p-cpe:/a:centos:centos:pcs-snmp, p-cpe:/a:redhat:enterprise_linux:grafana-cloudwatch, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:centos:centos:grafana-postgres, p-cpe:/a:redhat:enterprise_linux:grafana-selinux, p-cpe:/a:centos:centos:gjs-devel, p-cpe:/a:redhat:enterprise_linux:sgx-common, p-cpe:/a:redhat:enterprise_linux:grafana-graphite, p-cpe:/a:centos:centos:sgx-common, p-cpe:/a:redhat:enterprise_linux:grafana-mysql, p-cpe:/a:centos:centos:sgx-pckid-tool, p-cpe:/a:centos:centos:polkit-docs, p-cpe:/a:redhat:enterprise_linux:sgx-mpa, p-cpe:/a:centos:centos:grafana-mssql, p-cpe:/a:redhat:enterprise_linux:gjs-devel

Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Available: true

Exploit Ease: Exploits are available

Vulnerability Publication Date: 2/12/2026

Reference Information

CVE: CVE-2026-2391

Detections

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