Unsafe object property setter in mathjs

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.8 · CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2026-40897: 0.55% estimated exploitation activity in the next 30 days; percentile 46.11 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact This security 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. Patches The issue was introduced in mathjs v13.1.1, and patched in mathjs v15.2.0. Workarounds There is no workaround without upgrading to v15.2.0. References You can find out more via the commit fixing this issue: https://github.com/josdejong/mathjs/commit/513ab2a0e01004af91b31aada68fae8a821326ad (part of PR https://github.com/josdejong/mathjs/pull/3656).

Published by the source

16 Apr 2026, 22:38 UTC

Last modified by the source

10 Sep 2026, 03:50 UTC

Source last checked

26 Oct 2026, 12:51 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-29qv-4j9f-fjw5

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-29qv-4j9f-fjw5

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# Patch Next advisory brief: CVE-2026-40897

Advisory: Unsafe object property setter in mathjs
IDs: CVE-2026-40897, GHSA-29qv-4j9f-fjw5
Record: https://patchnext.com/advisories/cve-2026-40897 (revision 2, source checked 26 Oct 2026, 12:51 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: mathjs 15.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm mathjs: affected >= 13.1.1, < 15.2.0; fixed in 15.2.0

## Suggested inspection (read-only)
- `npm ls mathjs --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on mathjs.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-29qv-4j9f-fjw5 (OSV record GHSA-29qv-4j9f-fjw5 lists affected ranges: npm mathjs >=13.1.1 <15.2.0 (fixed))
- Verified: https://github.com/advisories/GHSA-29qv-4j9f-fjw5 (GitHub-reviewed advisory GHSA-29qv-4j9f-fjw5 lists affected ranges: npm mathjs >=13.1.1 <15.2.0)

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