{"id":"CVE-2021-37705","aliases":["EUVD-2021-0160","GHSA-q5vh-6whw-x745","PYSEC-2021-344"],"status":"published","title":"Improper Authorization and Origin Validation Error in OneFuzz","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 \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.","severity":{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.02415,"percentile":0.84277,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-285","CWE-346","CWE-863"],"published":"2021-08-13T20:15:11Z","modified":"2026-10-20T10:54:50Z","fixes":[{"ecosystem":"PyPI","package":"onefuzz","fixed_in":["2.31.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"onefuzz","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.12.0"},{"fixed":"2.31.0"}]}]},{"source":"osv","ecosystem":"PyPI","package":"onefuzz","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.12.0"},{"fixed":"2.31.0"}]}],"versions":["2.12.0","2.13.0","2.14.0","2.15.0","2.16.0","2.17.0","2.18.0","2.19.0","2.20.0","2.21.0","2.22.0","2.23.0","2.23.1","2.24.0","2.25.0","2.25.1","2.26.0","2.26.1","2.27.0","2.28.0","2.29.0","2.29.1","2.30.0"]},{"source":"osv","ecosystem":"PyPI","package":"onefuzz","ranges":[{"type":"GIT","events":[{"introduced":"0"},{"fixed":"2fcb4998887959b4fa11894a068d689189742cb1"}]},{"type":"ECOSYSTEM","events":[{"introduced":"2.12.0"},{"fixed":"2.31.0"}]}],"versions":["2.12.0","2.13.0","2.14.0","2.15.0","2.16.0","2.17.0","2.18.0","2.19.0","2.20.0","2.21.0","2.22.0","2.23.0","2.23.1","2.24.0","2.25.0","2.25.1","2.26.0","2.26.1","2.27.0","2.28.0","2.29.0","2.29.1","2.30.0"]}],"products":[{"vendor":"microsoft","product":"onefuzz"}],"references":[{"url":"https://github.com/microsoft/onefuzz/security/advisories/GHSA-q5vh-6whw-x745","tags":["x_refsource_CONFIRM","x_transferred","Third Party Advisory","advisory","web"]},{"url":"https://github.com/microsoft/onefuzz/pull/1153","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/microsoft/onefuzz/commit/2fcb4998887959b4fa11894a068d689189742cb1","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory","fix","web"]},{"url":"https://github.com/microsoft/onefuzz/releases/tag/2.31.0","tags":["x_refsource_MISC","x_transferred","Release Notes","Third Party Advisory","advisory","web"]},{"url":"https://pypi.org/project/onefuzz/","tags":["x_refsource_MISC","x_transferred","Product","package"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2021-37705","tags":["advisory"]},{"url":"https://github.com/pypa/advisory-database/tree/main/vulns/onefuzz/PYSEC-2021-344.yaml","tags":["web"]},{"url":"https://pypi.org/project/onefuzz","tags":["web"]},{"url":"https://github.com/advisories/GHSA-q5vh-6whw-x745"},{"url":"https://github.com/microsoft/onefuzz","tags":["web"]}],"sources":{"cve":[{"id":"CVE-2021-37705","title":"Improper Authorization and Origin Validation Error in OneFuzz","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 \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.","status":"published","published":"2021-08-13T20:15:11Z","modified":"2024-08-04T01:23:01.448Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","level":"critical","assessor":"cna"}],"cwes":["CWE-285","CWE-346"],"updated_at":"2026-11-02T14:32:58.028461Z"}],"euvd":[{"id":"EUVD-2021-0160","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 \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.","status":"published","published":"2021-08-13T20:15:11Z","modified":"2024-08-04T01:23:01Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","level":"critical"}],"updated_at":"2026-11-03T03:24:27.254804Z"}],"ghsa":[{"id":"GHSA-q5vh-6whw-x745","title":"Improper Authorization and Origin Validation Error in OneFuzz","description":"## Impact\n\nStarting 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.\n\nTo be vulnerable, a OneFuzz deployment must be:\n* Version 2.12.0 or greater\n* Deployed with the non-default [`--multi_tenant_domain`](https://github.com/microsoft/onefuzz/blob/2.30.0/src/deployment/deploy.py#L1021) option\n\nThis can result in read/write access to private data such as:\n* Software vulnerability and crash information\n* Security testing tools\n* Proprietary code and symbols\n\nVia authorized API calls, this also enables tampering with existing data and unauthorized code execution on Azure compute resources.\n\n## Patches\n\nThis 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.\n\n## Workarounds\n\nUsers can restrict access to the tenant of a deployed OneFuzz instance \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.\n\n## References\n\nYou can find an overview of the Microsoft Identity Platform [here](https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-overview).  This vulnerability applies to the multi-tenant application pattern, as described [here](https://docs.microsoft.com/en-us/azure/active-directory/develop/howto-convert-app-to-be-multi-tenant).\n\n## For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [OneFuzz](https://github.com/microsoft/onefuzz)\n* Email us at [fuzzing@microsoft.com](mailto:fuzzing@microsoft.com)","status":"published","published":"2021-08-13T20:16:32Z","modified":"2024-10-07T16:44:39Z","cvss":[{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L","level":"critical"},{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","level":"critical"}],"cwes":["CWE-285","CWE-346","CWE-863"],"updated_at":"2026-11-02T14:38:08.742903Z"}],"nvd":[{"id":"CVE-2021-37705","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 \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.","status":"published","published":"2021-08-13T21:15:06.973Z","modified":"2026-06-17T04:01:01.42Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","level":"critical","assessor":"secondary"},{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical","assessor":"primary"},{"version":"2.0","score":6.8,"vector":"AV:N/AC:M/Au:N/C:P/I:P/A:P","level":"medium","assessor":"primary"}],"cwes":["CWE-285","CWE-346","CWE-863"],"updated_at":"2026-11-02T14:06:56.943671Z"}],"osv":[{"id":"CVE-2021-37705","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 \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.","status":"published","published":"2021-08-13T21:15:06.973Z","modified":"2026-10-20T10:54:50.629269501Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-02T15:44:20.434873Z"},{"id":"GHSA-q5vh-6whw-x745","title":"Improper Authorization and Origin Validation Error in OneFuzz","description":"## Impact\n\nStarting 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.\n\nTo be vulnerable, a OneFuzz deployment must be:\n* Version 2.12.0 or greater\n* Deployed with the non-default [`--multi_tenant_domain`](https://github.com/microsoft/onefuzz/blob/2.30.0/src/deployment/deploy.py#L1021) option\n\nThis can result in read/write access to private data such as:\n* Software vulnerability and crash information\n* Security testing tools\n* Proprietary code and symbols\n\nVia authorized API calls, this also enables tampering with existing data and unauthorized code execution on Azure compute resources.\n\n## Patches\n\nThis 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.\n\n## Workarounds\n\nUsers can restrict access to the tenant of a deployed OneFuzz instance \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.\n\n## References\n\nYou can find an overview of the Microsoft Identity Platform [here](https://docs.microsoft.com/en-us/azure/active-directory/develop/v2-overview).  This vulnerability applies to the multi-tenant application pattern, as described [here](https://docs.microsoft.com/en-us/azure/active-directory/develop/howto-convert-app-to-be-multi-tenant).\n\n## For more information\nIf you have any questions or comments about this advisory:\n* Open an issue in [OneFuzz](https://github.com/microsoft/onefuzz)\n* Email us at [fuzzing@microsoft.com](mailto:fuzzing@microsoft.com)","status":"published","published":"2021-08-13T20:16:32Z","modified":"2026-07-08T06:29:53.314609918Z","cvss":[{"version":"3.1","score":10,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:L","level":"critical"},{"version":"4.0","score":9.5,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:H/SI:H/SA:L","level":"critical"}],"cwes":["CWE-285","CWE-346","CWE-863"],"updated_at":"2026-11-02T15:46:54.055966Z"},{"id":"PYSEC-2021-344","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 \u003c 2.31.0 by redeploying in the default configuration, which omits the `--multi_tenant_domain` option.","status":"published","published":"2021-08-13T21:15:00Z","modified":"2023-11-08T04:06:23.491489Z","updated_at":"2026-11-02T15:52:52.682031Z"}]}}