CVE-2021-37705Improper Authorization and Origin Validation Error in OneFuzz
- 10.0CriticalCVSS base score
- 2.4%Exploitation in 30 daysEPSS · top 16% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
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.
Timeline
ID reserved
By GitHub_M
- 15 days later
· 15 days later
Published
- 3 years later
· 3 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Critical10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L |
| NVDNVD · Modified | 3.1 | Critical10.0 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 2.4% · top 16% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Critical 10.0.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- PyPIonefuzzGHSA-q5vh-6whw-x745 (opens in a new tab)
References
References5
- https://github.com/microsoft/onefuzz/security/advisories/GHSA-q5vh-6whw-x745 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://github.com/microsoft/onefuzz/pull/1153 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/microsoft/onefuzz/commit/2fcb4998887959b4fa11894a068d689189742cb1 (opens in a new tab)x_refsource_MISCx_transferred
- https://github.com/microsoft/onefuzz/releases/tag/2.31.0 (opens in a new tab)x_refsource_MISCx_transferred
- https://pypi.org/project/onefuzz/ (opens in a new tab)x_refsource_MISCx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2021-0160 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-q5vh-6whw-x745 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2021-37705)Record last updated .