Vulnerability · Published Sep 14, 2026 · Assigned by GitHub_M
CVE-2026-49250Conform: parseSubmission vulnerable to CPU exhaustion when parsing many unique form fields
High 8.7
In plain English
A high-severity security flaw in conform from edmundhung. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 44% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| npm | @conform-to/dom | 1.19.4 | GHSA-525m-7f82-2mf7 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| edmundhung | conform | >= 1.8.0, < 1.19.4 |
Weakness: CWE-407 · Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N