Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion. This vulnerability is fixed in 5.6.4.
History

Fri, 13 Mar 2026 00:15:00 +0000

Type Values Removed Values Added
Weaknesses CWE-843
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.9, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate


Thu, 12 Mar 2026 14:15:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 12 Mar 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Svelte
Svelte devalue
Vendors & Products Svelte
Svelte devalue

Wed, 11 Mar 2026 18:00:00 +0000

Type Values Removed Values Added
Description Svelte devalue is a JavaScript library that serializes values into strings when JSON.stringify isn't sufficient for the job. In devalue v5.6.3 and earlier, devalue.parse and devalue.unflatten were susceptible to prototype pollution via maliciously crafted payloads. Successful exploitation could lead to Denial of Service (DoS) or type confusion. This vulnerability is fixed in 5.6.4.
Title devalue has prototype pollution in devalue.parse and devalue.unflatten
Weaknesses CWE-1321
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-03-11T17:47:40.016Z

Updated: 2026-03-12T13:51:34.208Z

Reserved: 2026-03-04T17:23:59.797Z

Link: CVE-2026-30226

cve-icon Vulnrichment

Updated: 2026-03-12T13:51:30.426Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-11T18:16:22.937

Modified: 2026-03-12T21:08:22.643

Link: CVE-2026-30226

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-03-11T17:47:40Z

Links: CVE-2026-30226 - Bugzilla