CVE-2026-93363: Payload CMS storage-vercel-blob access control bypass in uploads

CVE-2026-93363 · Severity: medium · CVSS 4.3 · Published 2026-09-25

Payload CMS is a headless content management system that manages digital content and media assets. The Vercel Blob storage adapter contains a flaw that allows authenticated users to upload files without the proper collection-level permissions, bypassing intended access controls. An attacker with any authenticated account could upload unauthorized files or overwrite existing content.

Vendors: npm, Payload.

Quick answers

Is CVE-2026-93363 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-93363 being exploited in the wild.
How severe is CVE-2026-93363?
Medium severity, with a CVSS score of 4.3, published 25 September 2026.
Which products and versions are affected?
@payloadcms/storage-vercel-blob (npm) >= 3.25.0, < 3.90.0, SEMVER:introduced=3.25.0,fixed=3.90.0; Payload Storage-Vercel-Blob >=3.25.0, <3.90.0; >=4.0.0-canary.0, <4.0.0-canary.34.
Is there a fix for CVE-2026-93363?
Yes. @payloadcms/storage-vercel-blob (npm): upgrade to 3.90.0 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-93363 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-93363?
Check whether you run @payloadcms/storage-vercel-blob (npm) or Payload Storage-Vercel-Blob at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • @payloadcms/storage-vercel-blob (npm): upgrade to 3.90.0 or later
    npm install @payloadcms/storage-vercel-blob@3.90.0

Technical details

The @payloadcms/storage-vercel-blob adapter fails to enforce collection-level access controls on the client-upload route, allowing authenticated users to bypass intended authorization checks (CWE-862: Missing Authorization). An authenticated attacker can directly access the client-upload endpoint and upload files without possessing the required collection permissions. A fix is available in versions 3.90.0 or later and 4.0.0-canary.34 or later.

Affected products

  • Payload storage-vercel-blob >=3.25.0, <3.90.0; >=4.0.0-canary.0, <4.0.0-canary.34

Identifiers

  • CVE-2026-93363
  • GHSA-mc8m-rr6c-r5qr

Timeline

  • 2026-09-25: disclosed

References

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