Prototype Pollution in Svelte's Devalue Utility Library
CVE-2025-57820

7.9HIGH

Key Information:

Vendor

Sveltejs

Status
Devalue
Vendor
CVE Published:
26 August 2025

What is CVE-2025-57820?

The devalue utility library prior to version 5.3.2 is susceptible to a vulnerability where a string passed to devalue.parse could create objects with overridden properties. This flaw stems from inadequate validation of the proto property and could lead to prototype pollution, potentially compromising the integrity of the application. Users are strongly advised to upgrade to version 5.3.2 or later to mitigate this security issue.

Affected Version(s)

devalue < 5.3.2

References

https://github.com/sveltejs/devalue/security/advisories/G...
x_refsource_CONFIRM
https://github.com/sveltejs/devalue/commit/0623a47c9555b6...
x_refsource_MISC

CVSS V4

Score:
7.9
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.
CVE-2025-57820 : Prototype Pollution in Svelte's Devalue Utility Library