Parameter injection via predictable multipart boundaries
Published Jul 18, 2025 · Updated Nov 3, 2025
HTTP parameter pollution in form-data before 2.5.4, 3.0.0 through 3.0.3, and 4.0.0 through 4.0.3 allows remote attackers to inject fields. The _generateBoundary method in lib/form_data.js derives each multipart boundary from predictable Math.random() outputs, letting a crafted field terminate a part and introduce attacker-chosen fields. Exploitation requires observable application Math.random() values and control of a field sent by form-data; successful attacks can alter parameters in downstream internal requests.
Summary
What happened
HTTP parameter pollution in form-data before 2.5.4, 3.0.0 through 3.0.3, and 4.0.0 through 4.0.3 allows remote attackers to inject fields. The _generateBoundary method in lib/form_data.js derives each multipart boundary from predictable Math.random() outputs, letting a crafted field terminate a part and introduce attacker-chosen fields. Exploitation requires observable application Math.random() values and control of a field sent by form-data; successful attacks can alter parameters in downstream internal requests.
The record
- CVE
- CVE-2025-7783
- Published
- Jul 18, 2025
- Updated
- Nov 3, 2025
- Vendor
- form-data
- Product
- form-data
- Classifications
- CWE-330, CAPEC-460, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 18, 2025CVE publishedPublication date reported by the CVE source.
- Nov 3, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 2.5.4
- Affected versionversion=3.0.0 - 3.0.3
- Affected versionversion=4.0.0 - 4.0.3
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- CVE-2025-7783 proof of conceptproof of concept · demonstrated
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Technologies
Your stack
See the directory against your own environment.
Your stack
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