GitHub Advisoryadvisory · npm

GHSA-525m-7f82-2mf7 @conform-to/dom parseSubmission vulnerable to CPU exhaustion when parsing many unique form fields

HIGH Published 2026-07-02 Modified 2026-07-02 Official page ↗
Aliases
CVE-2026-49250
Ecosystem
npm
Packages
@conform-to/dom
Severity
High
CVSS 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
Weaknesses
CWE-407
Reviewed
2026-07-02

Affected packages

• npm @conform-to/dom: >= 1.8.0, < 1.19.4 → fixed in 1.19.4

Description

A CPU exhaustion vulnerability exists in Conform's `parseSubmission` future API when parsing `FormData` or `URLSearchParams` submissions with many unique field names. The parser previously looked up values by field name, which could require repeated scans of the submitted entries and cause excessive synchronous CPU work if an attacker supplies a crafted submission. > [!NOTE] > The patched version fixes this by iterating submitted entries directly instead of repeatedly looking up values by field name. Applications that accept untrusted form submissions should still enforce request parsing limits before passing data to Conform. For multipart requests, @remix-run/form-data-parser provides `maxParts`, `maxTotalSize`, `maxFileSize`, `maxFiles`, and `maxHeaderSize` options.

Related

Alias · CVE (1)

  • CVE-2026-49250 Conform, a type-safe form validation library, allows the parsing of nested objects in the form of object.property. vulnerability

Weakness · CWE (1)

  • CWE-407 Inefficient Algorithmic Complexity weakness

References