devalue: Malformed null-prototype object keys bypass __proto__ rejection via property-key coercion
This is another instance of https://github.com/sveltejs/devalue/security/advisories/GHSA-mwv9-gp5h-frr4, where some payloads could cause parse to create objects with a __proto__ own property. This on its own is not enough to cause prototype pollution, and indeed this is actually how JSON.parse works, but we decided to be a little more defensive here and not allow the creation of objects with __proto__ own-properties. It is very unlikely for this to cause any issues.
Affected software
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| Platform | Package | Vulnerable versions | Fixed in |
|---|---|---|---|
| npm package | devalue | < 5.9.3 | 5.9.3 |
References
- CVSS vector
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N- Weakness (CWE)
CWE-1321- Platform
- npm
- Package
devalue- Disclosed
- 01.10.2026
- Updated
- 11.10.2026 10:22
Sources and licenses
OSV / GitHub Advisory Database - GHSA-4q55-j62x-fr9h - CC BY 4.0
Vulnerability history: devalue
All published vulnerabilities of this package (npm package), newest first. Shows whether this is a one-off slip or a package that needs watching.
- Total entries
- 16
- First → latest
- 08.2025 10.2026
- Without a fix
- 0
- Exploited in attacks
- 0
Severity breakdown
- High 8
- Medium 4
- Low 4
Disclosures per year
- 2025: 1
- 2026: 15
-
devalue: Malformed null-prototype object keys bypass __proto__ rejection via property-key coercion this entry
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