CVE-2026-123567

LOWCVSS 3.7/10

Last modified

CVE-2026-123567 is a low-severity vulnerability rated 3.7/10 on the CVSS scale. Sveltejs devalue before 5.6.4 contains a prototype injection vulnerability that allows attackers to inject __proto__ own properties into objects returned by devalue.parse and devalue.unflatten. Attackers can supply crafted serialized input that, when downstream code merges results via Object.assign, alters the target object's prototype..

Description

Sveltejs devalue before 5.6.4 contains a prototype injection vulnerability that allows attackers to inject __proto__ own properties into objects returned by devalue.parse and devalue.unflatten. Attackers can supply crafted serialized input that, when downstream code merges results via Object.assign, alters the target object's prototype.

Metrics

Weakness Enumeration

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
sveltejsdevalue< 5.6.4

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-123567?
Sveltejs devalue before 5.6.4 contains a prototype injection vulnerability that allows attackers to inject __proto__ own properties into objects returned by devalue.parse and devalue.unflatten. Attackers can supply crafted serialized input that, when downstream code merges results via Object.assign, alters the target object's prototype.
How severe is CVE-2026-123567?
CVE-2026-123567 has a CVSS score of 3.7/10 (LOW severity).
How do I fix CVE-2026-123567?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST