What’s Vulnerable › Vulnerabilities

CVE-2026-33221: Nhost Storage Affected by MIME Type Spoofing via Trusted Client Content-Type Header in Storage Upload

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-20 · updated 2026-06-17
• Weakness: CWE-343

Description

Nhost is an open source Firebase alternative with GraphQL. Prior to version 0.12.0, the storage service's file upload handler trusts the client-provided Content-Type header without performing server-side MIME type detection. This allows an attacker to upload files with an arbitrary MIME type, bypassing any MIME-type-based restrictions configured on storage buckets. This issue has been patched in version 0.12.0.

Affected products

• nhost Storage: before 0.12.0 — fixed in 0.12.0

How to fix

Upgrade to a fixed version: nhost Storage 0.12.0. Check the vendor advisory for mitigations.

References

• https://github.com/nhost/nhost/commit/c4bd53f042d7f568e567e18e2665af81660fce85
• https://github.com/nhost/nhost/pull/4018
• https://github.com/nhost/nhost/releases/tag/storage%400.12.0
• https://github.com/nhost/nhost/security/advisories/GHSA-g9f6-9775-hffm

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