CVE-2026-49250Published

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

Collected exploitation and prediction evidence

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

cve-program · CVE-2026-49250

Published

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.

Source published: 14 Sep 2026 17:14:08 UTC
Source modified: 14 Sep 2026 19:01:26 UTC
Observed here: 23 Oct 2026 15:48:27 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · 8.7 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

euvd · EUVD-2026-77679

Published

EUVD source date text has no stated timezone and is retained without inventing a UTC instant. Related bulletin membership is not an alias, common cause or applicability claim. A missing vector with a zero score is treated as unrated. Complete vendor/product and underlying source evidence remains in the original JSON.

Original publisher date fields

datePublished: Sep 14, 2026, 5:14:08 PM

dateUpdated: Sep 14, 2026, 7:01:26 PM

Source published: Sep 14, 2026, 5:14:08 PM (timezone not stated)
Source modified: Sep 14, 2026, 7:01:26 PM (timezone not stated)
Observed here: 11 Nov 2026 13:03:26 UTC
Source terms: ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 8.7 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

nvd · CVE-2026-49250

Published

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Deferred

Weakness classifications: CWE-407

Original publisher date fields

published: 2026-09-14T18:17:49.360

lastModified: 2026-09-30T19:57:08.043

Source published: 14 Sep 2026 18:17:49 UTC
Source modified: 30 Sep 2026 19:57:08 UTC
Observed here: 25 Oct 2026 12:17:32 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 8.7 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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

osv · GHSA-525m-7f82-2mf7

Published

A CPU exhaustion vulnerability exists in Conform's [`parseSubmission`](https://conform.guide/api/react/future/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](https://www.npmjs.com/package/@remix-run/form-data-parser) provides `maxParts`, `maxTotalSize`, `maxFileSize`, `maxFiles`, and `maxHeaderSize` options.

Source published: 2 Jul 2026 19:18:41 UTC
Source modified: 10 Sep 2026 03:51:10 UTC
Observed here: 24 Oct 2026 13:17:17 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V4 · 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

Publisher rating · HIGH