Prototype pollution in silentmatt expr-eval
Priority HIGH 82CWE-1321Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 1 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA, GitHub and Red Hat.
Summary
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 it matters now
Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00851 58th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD and the CNA
Fix Partial expr-eval-fork (npm): 2.0.2Red Hat: 1 advisoryRed Hat: 1 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| silentmatt | expr-eval | up to 2.0.2 | — | No fix listed | CNA |
| — | expr-eval (npm) | up to 2.0.2 | — | No fix listed | GHSA-8gw3-rxh4-v6jx |
| — | expr-eval-fork (npm) | before 2.0.2 | 2.0.2 | Patch available | GHSA-8gw3-rxh4-v6jx |
- expr-eval Vendorsilentmatt Affected up to 2.0.2 Fixed in — No fix listed CNA
- expr-eval (npm) Vendor— Affected up to 2.0.2 Fixed in — No fix listed GHSA-8gw3-rxh4-v6jx
- expr-eval-fork (npm) Vendor— Affected before 2.0.2 Fixed in 2.0.2 Patch available GHSA-8gw3-rxh4-v6jx
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:silentmatt:javascript_expression_evaluator:*:*:*:*:*:node.js:*:* | all versions | Vulnerable | silentmatt |
- cpe:2.3:a:silentmatt:javascript_expression_evaluator:*:*:*:*:*:node.js:*:* Versions all versions Vulnerable ·silentmatt
Remediation
- Fix · GHSA-8gw3-rxh4-v6jx expr-eval-fork (npm) Fixed in 2.0.2 Advisory →
Red Hat 1 advisory
- RHSA-2026:0140 Released 2026-01-06 · Red Hat rating Importantgrafana-pcp security update
- Red Hat Enterprise Linux AppStream AUS (v. 8.2) grafana-pcp-1.0.5-5.el8_2
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 8 | Affected | No fix yet |
| Red Hat Enterprise Linux AI (RHEL AI) 3 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux AppStream AUS (v. 8.2) | Fixed | RHSA-2026:0140 |
Not affected: 1 product
- Red Hat Enterprise Linux AI (RHEL AI) 3
Timeline
- 2026-10-02 Threatist record created from CVE-2025-13204
- 2026-10-03 Alias added: GHSA-8gw3-rxh4-v6jx
- 2026-10-30 CVSS score changed · CISA ADP
- 2026-10-30 CISA SSVC decision points changed
- 2026-10-31 EPSS moved to the 50th–90th percentile
References
Exploit 2
Other 7
- https://www.npmjs.com/package/expr-eval-fork
- https://github.com/silentmatt/expr-eval
- https://github.com/jorenbroekema/expr-eval
- https://github.com/SECCON/SECCON2022_final_CTF/blob/main/jeopardy/web/babybox/solver/solver.py
- https://github.com/jorenbroekema/expr-eval/commit/6c475a118643ae0efe012de283e932fb8b74324b
- https://github.com/silentmatt/expr-eval/commit/6e889e0e75c50ac37d70c35388602025650e0c50
- https://www.huntr.dev/bounties/1-npm-expr-eval
More silentmatt Javascript Expression Evaluator vulnerabilities
- TI-2025-11671 Code injection in silentmatt expr-eval CVSS 3.1CRITICAL 9.8
Sources
- CVE-2025-13204 · CVE Program
- CVE-2025-13204 · NVD
- FIRST EPSS
- GHSA-8gw3-rxh4-v6jx · GitHub Advisory Database · CC BY 4.0
- CVE-2025-13204 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences