How severe is GHSA-mc8m-rr6c-r5qr?

GHSA-mc8m-rr6c-r5qr has a CVSS score of 4.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by GHSA-mc8m-rr6c-r5qr?

GHSA-mc8m-rr6c-r5qr affects the following packages: @payloadcms/storage-vercel-blob (npm), @payloadcms/storage-vercel-blob (npm). Ecosystems affected: npm.

How do I fix GHSA-mc8m-rr6c-r5qr?

Update @payloadcms/storage-vercel-blob to 3.90.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mc8m-rr6c-r5qr is resolved across your whole dependency graph.

How do I detect GHSA-mc8m-rr6c-r5qr in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @payloadcms/storage-vercel-blob, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate GHSA-mc8m-rr6c-r5qr if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is GHSA-mc8m-rr6c-r5qr actively exploited in the wild?

No public exploit code has been indexed for GHSA-mc8m-rr6c-r5qr yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for GHSA-mc8m-rr6c-r5qr?

GHSA-mc8m-rr6c-r5qr has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 7th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is GHSA-mc8m-rr6c-r5qr?

GHSA-mc8m-rr6c-r5qr is classified as CWE-862 (CWE-862). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was GHSA-mc8m-rr6c-r5qr published, and has it been updated?

GHSA-mc8m-rr6c-r5qr was published on November 4, 2026 and was last updated on November 4, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦

📦 npm

Not in CISA KEV

MEDIUM severity

@payloadcms/storage-vercel-blob has access control bypass of uploads in Vercel Storage adapterGHSA-mc8m-rr6c-r5qr

MEDIUMFix: payloadcms/payload@47abe9b

GHSA-mc8m-rr6c-r5qr is a medium-severity (CVSS 4.3) CWE-862 vulnerability in @payloadcms/storage-vercel-blob. A fix is available for @payloadcms/storage-vercel-blob — see the affected versions and patch details below.

Also known asCVE-2026-93363

Published

Nov 4, 2026

Updated

Nov 4, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for GHSA-mc8m-rr6c-r5qr.

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs7th percentile — riskier than 7% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.

8other npm packages depend on this — each one inherits the vulnerability until it's patched upstream

@payloadcms/storage-vercel-blobnpm

204Kdownloads / week

Description

Impact

In affected configurations, client upload access does not consistently align with the associated collection’s access configuration.

You are affected if:

You use client uploads with @payloadcms/storage-vercel-blob.
Authenticated users can access the client-upload route.

Applications that do not enable client uploads are not affected.

Patches

Client uploads now require authentication and the appropriate collection-level access before upload access is granted.

Users should upgrade Payload packages to >= 3.90.0 or >= 4.0.0-canary.34.

Workarounds

Upgrading to a patched version is recommended. Until you can upgrade, disable client uploads or configure the upload route’s access control to enforce the associated collection’s permissions.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`@payloadcms/storage-vercel-blob`	≥ 3.25.0&&< 3.90.0	3.90.0`npm install @payloadcms/storage-vercel-blob@3.90.0`
📦npm	`@payloadcms/storage-vercel-blob`	≥ 4.0.0-canary.0&&< 4.0.0-canary.34	4.0.0-canary.34`npm install @payloadcms/storage-vercel-blob@4.0.0-canary.34`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @payloadcms/storage-vercel-blob, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @payloadcms/storage-vercel-blob to 3.90.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-mc8m-rr6c-r5qr is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Frequently Asked Questions

### Impact In affected configurations, client upload access does not consistently align with the associated collection’s access configuration. You are affected if: - You use client uploads with `@payloadcms/storage-vercel-blob`. - Authenticated users can access the client-upload route. Applications that do not enable client uploads are not affected. ### Patches Client uploads now require authentication and the appropriate collection-level access before upload access is granted. Users should upgrade Payload packages to `>= 3.90.0` or `>= 4.0.0-canary.34`. ### Workarounds Upgrading to a pat