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Vulnerability · Published Sep 8, 2026 · Assigned by VulDB

CVE-2026-86716Cesanta mJS mjs_tok.c skip_spaces_and_comments heap-based overflow

High 7.3

In plain English

A high-severity heap buffer overflow in mJS from Cesanta. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities).

Severity (CVSS 3.1)7.3High
Exploit odds (30 days)0.6%top 52.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

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.

Affected products (as reported)

VendorProductVersions
Cesanta mJS 1.01.11.21.31.41.51.61.7

Weakness: CWE-122, CWE-119 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L/E:P/RL:X/RC:R

References