CVE-2025-13204: javascript Prototype Pollution

Description

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.

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CVSS v3.1 Score

7.3

HIGH

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

Weakness Type (CWE)

CWE-1321 CWE-1321

Affected Products

Vendor	Product	Versions
silentmatt	javascript_expression_evaluator	All

References

Advisories & Patches

https://github.com/silentmatt/expr-eval/pull/252/files

Exploits

https://www.huntr.dev/bounties/1-npm-expr-eval/

Other References

https://github.com/SECCON/SECCON2022_final_CTF/blob/main/jeopardy/web/babybox/solver/solver.py https://github.com/jorenbroekema/expr-eval https://github.com/silentmatt/expr-eval https://github.com/vladko312/extras/blob/f549d505af300fd74a01b46fab2102990ff1c14d/expr-eval.py https://www.npmjs.com/package/expr-eval-fork

Frequently Asked Questions

What is CVE-2025-13204? +

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. It has a CVSS v3.1 base score of 7.3 (HIGH).

How severe is CVE-2025-13204? +

CVE-2025-13204 has a CVSS v3.1 score of 7.3 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching.

What products are affected by CVE-2025-13204? +

CVE-2025-13204 affects products from silentmatt, specifically: javascript_expression_evaluator. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2025-13204? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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