dbcve.org
OnefuzzApplication · Microsoft

CVE-2021-37705

CRITICAL · 10.0 CVSS v3.1 Published 2021-08-13
Fix available
A fix is available. Upgrade to 2.31.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

OneFuzz versions 2.12.0 through 2.30.x with the non-default --multi_tenant_domain option enabled lack proper bearer token issuer validation, allowing authenticated users from ANY Azure Active Directory tenant to make authorized API calls. This grants attackers read/write access to sensitive vulnerability/crash data, security tools, and code, plus the ability to execute unauthorized code on Azure compute resources.

MitigationUpgrade OneFuzz to version 2.31.0 or later and configure the application-level bearer token issuer allowlist as documented. Alternatively, redeploy with default configuration (without --multi_tenant_domain) as a workaround.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
OnefuzzApplication
Affected:>= 2.12.0, < 2.31.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Determine OneFuzz version
    Run the OneFuzz CLI command to retrieve the installed version, such as 'onefuzz --version' or check the version reported in the deployment manifests
    Affected if Version is 2.12.0 through 2.30.x (any version >= 2.12.0 and < 2.31.0)
  2. Locate OneFuzz deployment configuration
    Identify the deployment configuration files or Helm values used when deploying OneFuzz to the cluster, typically found in the infrastructure-as-code templates or deployment scripts
    Affected if Configuration files exist showing OneFuzz deployment
  3. Verify multi_tenant_domain setting
    Inspect the OneFuzz deployment configuration for the --multi_tenant_domain flag or multi_tenant_domain parameter - check whether it is explicitly set to a value (non-default) or enabled in the configuration
    Affected if The --multi_tenant_domain option is present and set to a non-default value (indicating it is enabled)
  4. Confirm affected version and configuration combination
    Cross-reference the installed version against the affected range AND verify that multi_tenant_domain is enabled in the active configuration
    Affected if Both conditions are true: version >= 2.12.0 AND < 2.31.0 AND multi_tenant_domain is enabled

Environment is affected if OneFuzz version is 2.12.0 through 2.30.x AND the non-default --multi_tenant_domain option is enabled in the deployment configuration.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.31.0 or later
Fixed in 2.31.0
Vendor patch github.com →
Interim mitigation

Upgrade OneFuzz to version 2.31.0 or later and configure the application-level bearer token issuer allowlist as documented. Alternatively, redeploy with default configuration (without --multi_tenant_domain) as a workaround.

Recommended fix High confidence

OneFuzz 2.31.0 or later

  1. Upgrade OneFuzz to version 2.31.0 or later to apply the vendor patch that adds application-level validation of bearer token issuer against an administrator-configured allowlist
  2. After upgrading, configure the issuer allowlist in the OneFuzz deployment to ensure only authorized Azure AD tenants can access the API
  3. If immediate upgrade is not feasible, redeploy OneFuzz using the default configuration (without the --multi_tenant_domain option) as a workaround to restrict access to the tenant where the instance is deployed
Caveat The upgrade introduces a new issuer validation feature that requires administrator configuration of allowed token issuers; ensure the issuer allowlist is properly configured after upgrading to maintain multi-tenant access if needed

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Onefuzz Scoped from the published advisory
  • Consultation6.0 h
  • Implementation12.0 h
  • Testing8.0 h
  • Review / QA4.0 h
30.0 hours of engineering $5,280
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,448.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-37705 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data