Buffer overflow in Cesanta Mjs
CVE-2026-86716
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.
Vulnerability class: Buffer Overflow
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.3 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L.
EPSS exploit prediction
EPSS: 0.006 (46.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 46th percentile — 46.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Cesanta Mjs — versions 1.0, 1.1, 1.10
Weakness classification (CWE)
References
- vuldb.com/vuln/399773 (technical-description, vdb-entry)
- vuldb.com/vuln/399773/cti (signature, permissions-required)
- vuldb.com/cve/CVE-2026-86716 (third-party-advisory)
- vuldb.com/submit/910881 (third-party-advisory)
- vuldb.com/submit/910882 (third-party-advisory)
- github.com/cesanta/mjs/issues/324 (issue-tracking, exploit)
- github.com/cesanta/mjs/ (product)
Frequently asked questions
- What is CVE-2026-86716?
- CVE-2026-86716 is a high-severity vulnerability in Cesanta Mjs, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.3/10. Published 2026-09-08.
- How severe is CVE-2026-86716?
- High severity. CVSS v3 base score is 7.3 out of 10.