Prototype Pollution in Silentmatt Expr-Eval
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.
Vulnerability class: Prototype Pollution
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: 0.005 (36.8th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 37th percentile — 36.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000
Affected products
Weakness classification (CWE)
References
- www.npmjs.com/package/expr-eval-fork (Product)
- github.com/silentmatt/expr-eval (Product)
- github.com/jorenbroekema/expr-eval (Product)
- www.huntr.dev/bounties/1-npm-expr-eval/ (Exploit, Third Party Advisory, third-party-advisory)
- github.com/SECCON/SECCON2022_final_CTF/blob/main/jeopardy/web/babybox/solver/so… (Product)
- github.com/silentmatt/expr-eval/pull/252/files (Patch, patch, Issue Tracking)
- github.com/vladko312/extras/blob/f549d505af300fd74a01b46fab2102990ff1c14d/expr-… (Product, exploit)
Frequently asked questions
- What is CVE-2025-13204?
- CVE-2025-13204 is a high-severity vulnerability in Silentmatt Expr-Eval, classified under Improperly Controlled Modification of Object Prototype Attributes (Prototype Pollution). CVSS score: 7.3/10. Published 2025-11-14.
- How severe is CVE-2025-13204?
- High severity. CVSS v3 base score is 7.3 out of 10.