---
id: CVE-2026-86716
title: A vulnerability was determined in Cesanta mJS up to 1.26
summary: >-
  A vulnerability was determined in Cesanta mJS up to 1.26. Affected is the
  function skip_spaces_and_comments of the file src/mjs_tok.c. Executing a
  manipulation can lead to heap-based buffer overflow. The attack can be
  launched remotely. …
severity: high
cvss: 7.3
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L'
cwe:
  - CWE-119
  - CWE-122
vendor: Cesanta
product: mJS
affected:
  - mJS 1.0
  - mJS 1.1
  - mJS 1.2
  - mJS 1.3
  - mJS 1.4
  - mJS 1.5
  - mJS 1.6
  - mJS 1.7
  - mJS 1.8
  - mJS 1.9
  - mJS 1.10
  - mJS 1.11
  - mJS 1.12
  - mJS 1.13
  - mJS 1.14
  - mJS 1.15
  - mJS 1.16
  - mJS 1.17
  - mJS 1.18
  - mJS 1.19
  - mJS 1.20
  - mJS 1.21
  - mJS 1.22
  - mJS 1.23
  - mJS 1.24
  - mJS 1.25
  - mJS 1.26
published: '2026-09-08'
updated: '2026-09-08'
sourceUpdated: '2026-09-08T20:18:53.110'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-86716'
references:
  - url: 'https://github.com/cesanta/mjs/'
    label: cna@vuldb.com
  - url: 'https://github.com/cesanta/mjs/issues/324'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/cve/CVE-2026-86716'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/submit/910881'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/submit/910882'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/399773'
    label: cna@vuldb.com
  - url: 'https://vuldb.com/vuln/399773/cti'
    label: cna@vuldb.com
tags:
  - nvd
  - cve.org
  - exploit-available
exploitAvailable: true
ssvc:
  exploitation: poc
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-09-08T19:07:17.867378Z'
ingestedAt: '2026-09-08T19:08:49.637Z'
epss: 0.0057
epssPercentile: 0.44855
---

## Overview

A vulnerability was determined in Cesanta mJS up to 1.26. Affected is the function skip_spaces_and_comments of the file src/mjs_tok.c. Executing a manipulation can lead to heap-based buffer overflow. The attack can be launched remotely. The exploit has been publicly disclosed and may be utilized. The project was informed of the problem early through an issue report but has not responded yet.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.