Security readout for executives and security teams
Plain-English summary
A vulnerable OneFuzz deployment could trust users from the wrong Azure Active Directory tenant. If exposed, outsiders with Azure AD identities could access or change sensitive fuzzing data, including crash details, security tools, proprietary code, and symbols.
Executive priority
Treat this as urgent for any affected OneFuzz deployment because the data involved may include vulnerability findings and proprietary code. If OneFuzz is not used, or only default configurations exist, business exposure is likely low.
Technical view
OneFuzz versions 2.12.0 through before 2.31.0 are affected only when deployed with the non-default --multi_tenant_domain option. The issue is incomplete authorization and origin validation: bearer token issuer validation was missing until 2.31.0 added an administrator-configured issuer allowlist.
Likely exposure
Exposure is limited to self-hosted OneFuzz instances on affected versions using --multi_tenant_domain. Default deployments without that option are described as the workaround path and are not the named vulnerable configuration.
Exploitation context
The bundle does not report active exploitation, and KEV is false. The advisory impact is still severe: unauthorized API access can read or modify private fuzzing data and enable code execution on Azure compute resources.
Researcher notes
The vulnerable condition is specific: OneFuzz >=2.12.0 and <2.31.0 plus non-default multi-tenant configuration. The fix added application-level issuer validation against an allowlist. Avoid assuming broader Microsoft or Azure product exposure.
Mitigation direction
- Upgrade OneFuzz to release 2.31.0 or later.
- For older deployments, redeploy with default configuration omitting --multi_tenant_domain.
- Confirm bearer token issuer allowlisting is configured after upgrade.
- Review Microsoft advisory and release notes before operational changes.
Validation and detection
- Inventory all self-hosted OneFuzz deployment versions.
- Check whether --multi_tenant_domain was used in deployment configuration.
- Verify upgraded instances are 2.31.0 or later.
- Review API and Azure AD logs for unexpected cross-tenant access.
- Check sensitive fuzzing artifacts for unauthorized changes.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-285: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-346: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCredential and access behavior lookup
The CVE wording references authentication or credential exposure, so valid-account and credential-access review may help. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2021-37705 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 10 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L3.96Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
10CriticalVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/microsoft/onefuzz/security/advisories/GHSA-q5vh-6whw-x745CVE reference · x_refsource_CONFIRM
- https://github.com/microsoft/onefuzz/pull/1153CVE reference · x_refsource_MISC
- https://github.com/microsoft/onefuzz/commit/2fcb4998887959b4fa11894a068d689189742cb1CVE reference · x_refsource_MISC
- https://github.com/microsoft/onefuzz/releases/tag/2.31.0CVE reference · x_refsource_MISC
- https://pypi.org/project/onefuzz/CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Authorization
Improper Authorization represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Origin Validation Error
Origin Validation Error represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.