CVE-2026-86716
Cesanta mJS mjs_tok.c skip_spaces_and_comments heap-based overflow
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.
INFO
Published Date :
Sept. 8, 2026, 7:20 p.m.
Last Modified :
Sept. 8, 2026, 8:18 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 2.0 | HIGH | [email protected] | ||||
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Cesanta mJS to a version that fixes the vulnerability.
- Apply patches if available from the vendor.
- Monitor for vendor security advisories.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-86716.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-86716 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-86716
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-86716 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-86716 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 08, 2026
Action Type Old Value New Value Added SSVC {'id': 'CVE-2026-86716', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'yes'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-08T19:07:17.867378Z'} -
New CVE Received by [email protected]
Sep. 08, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L Added CVSS V2 (AV:N/AC:L/Au:N/C:P/I:P/A:P) Added CWE CWE-119 Added CWE CWE-122 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/86xxx/CVE-2026-86716.json">CVE-2026-86716</a> Added Reference https://github.com/cesanta/mjs/ Added Reference https://github.com/cesanta/mjs/issues/324 Added Reference https://vuldb.com/cve/CVE-2026-86716 Added Reference https://vuldb.com/submit/910881 Added Reference https://vuldb.com/submit/910882 Added Reference https://vuldb.com/vuln/399773 Added Reference https://vuldb.com/vuln/399773/cti