Improper Authorization and Origin Validation Error in OneFuzz
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Security bypass
- Confidentiality · integrity · availability
- High · High · Low
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and GitHub. Impact type from CWE-285.
Summary
OneFuzz is an open source self-hosted Fuzzing-As-A-Service platform. Starting with OneFuzz 2.12.0 or greater, an incomplete authorization check allows an authenticated user from any Azure Active Directory tenant to make authorized API calls to a vulnerable OneFuzz instance. To be vulnerable, a OneFuzz deployment must be both version 2.12.0 or greater and deployed with the non-default --multi_tenant_domain option. This can result in read/write access to private data such as software vulnerability and crash information, security testing tools and proprietary code and symbols. Via authorized API calls, this also enables tampering with existing data and unauthorized code execution on Azure compute resources. This issue is resolved starting in release 2.31.0, via the addition of application-level check of the bearer token's `issuer` against an administrator-configured allowlist. As a workaround users can restrict access to the tenant of a deployed OneFuzz instance < 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Microsoft | onefuzz | 2.12.0 to before 2.31.0 | 2.31.0 | Patch available | CNA |
| — | onefuzz (PyPI) | 2.12.0 to before 2.31.0 | 2.31.0 | Patch available | GHSA-q5vh-6whw-x745 |
- onefuzz VendorMicrosoft Affected 2.12.0 to before 2.31.0 Fixed in 2.31.0 Patch available CNA
- onefuzz (PyPI) Vendor— Affected 2.12.0 to before 2.31.0 Fixed in 2.31.0 Patch available GHSA-q5vh-6whw-x745
Remediation
- Fix · CNA onefuzz (microsoft) Fixed in 2.31.0
- Fix · GHSA-q5vh-6whw-x745 onefuzz (PyPI) Fixed in 2.31.0 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2021-37705
- 2026-10-03 Alias added: GHSA-q5vh-6whw-x745
References
Patch 2
Advisory 3
Sources
- CVE-2021-37705 · CVE Program
- CVE-2021-37705 · NVD
- FIRST EPSS
- GHSA-q5vh-6whw-x745 · GitHub Advisory Database · CC BY 4.0
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