Prototype pollution via unfiltered INI section names
Published May 7, 2026 · Updated May 7, 2026
Prototype pollution in parse-ini 1.0.6 allows remote attackers to modify inherited object properties via a crafted INI file. The index.js assignments at lines 101 and 104 accept an attacker-controlled proto section without rejecting prototype keys, writing its properties into the global object prototype. Exploitation requires an application to parse attacker-supplied INI data; inherited properties can then alter application behavior, with code execution or denial of service dependent on available application gadgets.
Summary
What happened
Prototype pollution in parse-ini 1.0.6 allows remote attackers to modify inherited object properties via a crafted INI file. The index.js assignments at lines 101 and 104 accept an attacker-controlled proto section without rejecting prototype keys, writing its properties into the global object prototype. Exploitation requires an application to parse attacker-supplied INI data; inherited properties can then alter application behavior, with code execution or denial of service dependent on available application gadgets.
The record
- CVE
- CVE-2025-63703
- Published
- May 7, 2026
- Updated
- May 7, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-1321
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 7, 2026CVE publishedPublication date reported by the CVE source.
- May 7, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
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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
- Crafted __proto__ INI proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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