RCE in Josdejong Mathjs

CVE-2026-40897

Math.js is an extensive math library for JavaScript and Node.js. From 13.1.1 to before 15.2.0, a vulnerability allowed executing arbitrary JavaScript via the expression parser of mathjs. You can be affected when you have an application where users can evaluate arbitrary expressions using the mathjs expression parser. This vulnerability is fixed in 15.2.0.

Vulnerability class: Mass Assignment

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.008 (53.6th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-40897: held from 0.006 to 0.008.

EPSS over last 30 days · oldest: 0.006 · newest: 0.008 · change: +0.002

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2026-40897?
CVE-2026-40897 is a high-severity vulnerability in Josdejong Mathjs, classified under Improperly Controlled Modification of Dynamically-Determined Object Attributes. CVSS score: 8.8/10. Published 2026-04-24.
How severe is CVE-2026-40897?
High severity. CVSS v3 base score is 8.8 out of 10.
Is CVE-2026-40897 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.