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High · 8.7 CVE-2026-49250 EUVD-2026-77679GHSA-525m-7f82-2mf7

Conform: parseSubmission vulnerable to CPU exhaustion when parsing many unique form fields

Published Sep 14, 2026 · Updated Sep 14, 2026 · Assigned by GitHub_M

Description

Conform, a type-safe form validation library, allows the parsing of nested objects in the form of object.property. From 1.8.0 until 1.19.4, the parseSubmission future API in packages/conform-dom/formdata.ts repeatedly scans FormData or URLSearchParams entries by each unique field name. An unauthenticated attacker can submit a crafted form containing many unique names, causing excessive synchronous CPU work and denial of service in an application that passes the submission to parseSubmission. Applications should continue to enforce request parsing limits before invoking Conform. This issue is fixed in version 1.19.4.

Affected products

VendorProductAffectedFixed
edmundhung conform >= 1.8.0, < 1.19.4 —

Affected packages

EcosystemPackageAffectedFixedRecord
npm @conform-to/dom >= 1.8.0, < 1.19.4 1.19.4 GHSA-525m-7f82-2mf7

References