GHSA-g9f6-9775-hffm is a medium-severity (CVSS 5.3) CWE-343 vulnerability in github.com/nhost/nhost. A fix is available for github.com/nhost/nhost — see the affected versions and patch details below.
Nhost Storage Affected by MIME Type Spoofing via Trusted Client Content-Type Header in Storage Upload
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-g9f6-9775-hffm.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-g9f6-9775-hffm plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 379,145 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
github.com/nhost/nhostReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
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.
Affected Component
- Service:
services/storage - File:
services/storage/controller/upload_files.go - Function:
getMultipartFile(lines 48-70)
Root Cause
In getMultipartFile, if the client provides a non-empty Content-Type header that isn't application/octet-stream, the function returns it as-is without performing content-based detection:
contentType := file.header.Header.Get("Content-Type")
if contentType != "" && contentType != "application/octet-stream" {
return fileContent, contentType, nil // skip detection entirely
}
// mimetype.DetectReader only reached if client sends no Content-Type
// or sends application/octet-stream
mt, err := mimetype.DetectReader(fileContent)
Impact
Incorrect MIME type in file metadata. The MIME type stored in file metadata reflects what the client claims rather than what the file actually contains. Any system consuming this metadata (browsers, CDNs, applications) may handle the file incorrectly based on the spoofed type.
Suggested Fix
Always detect MIME type from file content using mimetype.DetectReader, ignoring the client-provided Content-Type header entirely.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/nhost/nhost | all versions | 0.0.0-20260318074820-c4bd53f042d7go get github.com/nhost/nhost@v0.0.0-20260318074820-c4bd53f042d7 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/nhost/nhost, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/nhost/nhost to 0.0.0-20260318074820-c4bd53f042d7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g9f6-9775-hffm is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-g9f6-9775-hffm can be triaged on real exposure rather than presence alone.
Tailored to GHSA-g9f6-9775-hffm. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-g9f6-9775-hffm in your dependencies?
O3 Security finds GHSA-g9f6-9775-hffm across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.