CVE-2025-13204: npm package `expr-eval` is vulnerable to Prototype Pollution

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HIGH 7.3REMOTEMITIGATE

CVE-2025-13204 is a high-severity flaw (CVSS 7.3) affecting javascript expression evaluator. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

npm package `expr-eval` is vulnerable to Prototype Pollution. An attacker with access to express eval interface can use JavaScript prototype-based inheritance model to achieve arbitrary code execution. The npm expr-eval-fork package resolves this issue.

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.3 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 58%)
CISA exploited list	No
Weakness	CWE-1321
Published	2025-11-14
Last modified	2026-10-07

Publisher (CNA): CERT/CC · Vendor: silentmatt

Last updated 2026-10-07 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-11-14 17:16 UTCPublished CVE record published
2026-10-07 21:10 UTCUpdated Record last modified

silentmatt javascript expression evaluator MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls javascript-expression-evaluator

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-13204?

javascript expression evaluator: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-13204 being exploited?

CVE-2025-13204 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-13204 affect?

CVE-2025-13204 affects javascript expression evaluator. Severity is high (CVSS 7.3). npm package `expr-eval` is vulnerable to Prototype Pollution. An attacker with access to express eval interface can use JavaScript prototype-based inheritance model to achieve arbitrary code execution. The npm expr-eval-fork package resolve

How urgent is CVE-2025-13204?

Priority 46/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Software pages

npm packages vulnerabilities

Related CVEs

CVE-2025-12735 CRITICAL 9.8 DOWNGRADE UPGRADE The expr-eval library is a JavaScript expression parser and evaluator designed to safely evaluate mathematical

References

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