# CVE-2026-34750: Payload has Insufficient Filename Validation in Client-Upload Signed-URL Endpoints

> Attackers can escape intended storage locations via crafted filenames in client-upload signed-URL endpoints of Payload CMS storage plugins.

- **Severity:** Medium 6.5 (`CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Apr 2026
- **Updated:** 2 Apr 2026
- **Also known as:** GHSA-frq9-7j6g-v74x

## What is CVE-2026-34750?

CVE-2026-34750 is a medium-severity path traversal vulnerability in payloadcms payload, published on 1 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.

### Official description

Payload is a free and open source headless content management system. Prior to version 3.78.0 in @payloadcms/storage-azure, @payloadcms/storage-gcs, @payloadcms/storage-r2, and @payloadcms/storage-s3, the client-upload signed-URL endpoints for S3, GCS, Azure, and R2 did not properly sanitize filenames. An attacker could craft filenames to escape the intended storage location. This issue has been patched in version 3.78.0 for @payloadcms/storage-azure, @payloadcms/storage-gcs, @payloadcms/storage-r2, and @payloadcms/storage-s3.

Weakness: CWE-22 (Improper Limitation of a Pathname to a Restricted Directory)

## Which versions are affected by CVE-2026-34750?

8 open source packages ship an affected version, including @payloadcms/storage-azure, @payloadcms/storage-gcs and @payloadcms/storage-r2. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `@payloadcms/storage-azure` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-azure` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-gcs` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-gcs` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-r2` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-r2` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-s3` | npm | All versions | 3.78.0 |
| `@payloadcms/storage-s3` | npm | All versions | 3.78.0 |

Products: Payloadcms Payload.

## How do I fix CVE-2026-34750?

Upgrade @payloadcms/storage-azure to 3.78.0 or later.

## Is CVE-2026-34750 being exploited?

There is no known exploitation of CVE-2026-34750 in the wild and no public exploit code.

## Other vulnerabilities in payloadcms payload

- [CVE-2026-105857](https://insights.sbomify.com/CVE-2026-105857/): Payload: RCE in Payload Form Builder (critical 10.0)
- [CVE-2026-105859](https://insights.sbomify.com/CVE-2026-105859/): Payload: Unauthorized update to collection documents (critical 9.8)
- [CVE-2026-25544](https://insights.sbomify.com/CVE-2026-25544/): Payload has an SQL Injection in JSON/RichText Queries on PostgreSQL/SQLite Adapters (critical 9.8)
- [CVE-2022-27952](https://insights.sbomify.com/CVE-2022-27952/): Unrestricted Upload of File with Dangerous Type in Payload (critical 9.8)
- [CVE-2026-105851](https://insights.sbomify.com/CVE-2026-105851/): Payload: Field access control bypass on auth collections (critical 9.3)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34750 and fix it if it is affected.

What it is: CVE-2026-34750 is a medium-severity path traversal vulnerability in payloadcms payload, published on 1 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-34750 in the wild and no public exploit code.

Affected packages and fixed versions:
- @payloadcms/storage-azure (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-azure (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-gcs (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-gcs (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-r2 (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-r2 (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-s3 (npm): affected all versions; fixed in 3.78.0
- @payloadcms/storage-s3 (npm): affected all versions; fixed in 3.78.0

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-34750/ (Markdown: https://insights.sbomify.com/CVE-2026-34750/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34750
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34750
- OSV: https://osv.dev/vulnerability/CVE-2026-34750

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34750/
Summaries are generated and may contain mistakes; the official description above is the record.