# @payloadcms/storage-vercel-blob has access control bypass of uploads in Vercel Storage adapter

Advisory record · `GHSA-mc8m-rr6c-r5qr`

- **Identifiers:** `GHSA-mc8m-rr6c-r5qr` · `CVE-2026-93363`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-862](https://cwe.mitre.org/data/definitions/862.html)
- **Tags:** [Broken access control](https://agentprime.io/advisories/tag/access-control.md)
- **Published:** 4 Nov 2026
- **Updated:** 4 Nov 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 4 Nov 2026, 17:00 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `@payloadcms/storage-vercel-blob` (npm): affected `>=3.25.0, <3.90.0 || >=4.0.0-canary.0, <4.0.0-canary.34`; fixed in `3.90.0`, `4.0.0-canary.34`

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.3 Medium, CVSS 4.0: `CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N`, from CNA (VulnCheck)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0018, the 7th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 4 Nov 2026, 17:00 UTC: [Confirmed by GitHub Advisory Database](https://github.com/advisories/GHSA-mc8m-rr6c-r5qr)
- 4 Nov 2026, 17:15 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-mc8m-rr6c-r5qr)

## Sources

- [GitHub Advisory Database: GHSA-mc8m-rr6c-r5qr](https://github.com/advisories/GHSA-mc8m-rr6c-r5qr)
- [OSV: GHSA-mc8m-rr6c-r5qr](https://osv.dev/vulnerability/GHSA-mc8m-rr6c-r5qr)
- <https://github.com/payloadcms/payload/security/advisories/GHSA-mc8m-rr6c-r5qr>
- <https://nvd.nist.gov/vuln/detail/CVE-2026-93363>
- <https://github.com/payloadcms/payload/commit/47abe9bb5c444330dbfaa9a5bc2033337932270b>
- <https://github.com/payloadcms/payload>
- <https://github.com/payloadcms/payload/releases/tag/v3.90.0>
- <https://www.vulncheck.com/advisories/payload-cms-storage-vercel-blob-adapter-improper-access-control-on-upload-route>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-mc8m-rr6c-r5qr>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-mc8m-rr6c-r5qr/>. Everything for agents: <https://agentprime.io/llms.txt>.