{"id":"CVE-2023-43645","aliases":["EUVD-2023-2394","GHSA-2hm9-h873-pgqh","GO-2023-2084"],"status":"published","title":"Denial of service from circular relationship definitions in OpenFGA","description":"OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.","severity":{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00937,"percentile":0.61098,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-835"],"published":"2023-09-26T20:58:17Z","modified":"2026-10-28T02:31:02Z","fixes":[{"ecosystem":"Go","package":"github.com/openfga/openfga","fixed_in":["1.3.2"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Go","package":"github.com/openfga/openfga","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.3.2"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/openfga/openfga","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.3.2"}]}]},{"source":"osv","ecosystem":"Go","package":"github.com/openfga/openfga","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"1.3.2"}]}]}],"products":[{"vendor":"openfga","product":"openfga"}],"references":[{"url":"https://github.com/openfga/openfga/security/advisories/GHSA-2hm9-h873-pgqh","tags":["x_refsource_CONFIRM","x_transferred","Vendor Advisory","advisory","web"]},{"url":"https://github.com/openfga/openfga/commit/725296025fd81227c89525808652c6acd4a605f6","tags":["x_refsource_MISC","x_transferred","Patch","fix","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2023-43645","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-2hm9-h873-pgqh"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/43xxx/CVE-2023-43645.json","tags":["advisory"]},{"url":"https://github.com/openfga/openfga","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2023-43645","title":"Denial of service from circular relationship definitions in OpenFGA","description":"OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.","status":"published","published":"2023-09-26T20:58:17.826Z","modified":"2024-09-23T20:20:10.674Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"cna"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:35:14.633899Z"}],"euvd":[{"id":"EUVD-2023-2394","description":"OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.","status":"published","published":"2023-09-26T20:58:17Z","modified":"2024-09-23T20:20:10Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"updated_at":"2026-11-03T00:28:16.146478Z"}],"ghsa":[{"id":"GHSA-2hm9-h873-pgqh","title":"OpenFGA Vulnerable to DoS from circular relationship definitions","description":"## Overview\nOpenFGA is vulnerable to a DoS attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die.\n\n## Am I Affected?\nYes, if your store contains an authorization model that allows circular relationships. For example, with this model:\n\n```\nmodel\n  schema 1.1\n\ntype user\n\ntype group\n  relations\n    define memberA: [user] or memberB or memberC or memberD or memberE\n    define memberB: [user] or memberA or memberC or memberD or memberE\n    define memberC: [user] or memberA or memberB or memberD or memberE\n    define memberD: [user] or memberA or memberB or memberC or memberE\n    define memberE: [user] or memberA or memberB or memberC or memberD\n```\n\nThis Check: `(user:anne, memberA, group:X)` can exhaust memory in the server.\n\n## Fix\nUpgrade to v1.3.2 and update any offending models.\n\n  **[BREAKING]** If your model contained cycles or a relation definition that has the relation itself in its evaluation path, then Checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. You will need to update your models to remove the cycles.","status":"published","published":"2023-09-28T21:27:04Z","modified":"2023-11-10T05:05:26Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:37:19.438667Z"}],"nvd":[{"id":"CVE-2023-43645","description":"OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.","status":"published","published":"2023-09-27T15:19:34.33Z","modified":"2026-06-17T06:26:08.63Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"secondary"},{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium","assessor":"primary"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T14:08:31.699785Z"}],"osv":[{"id":"CVE-2023-43645","title":"Denial of service from circular relationship definitions in OpenFGA","description":"OpenFGA is an authorization/permission engine built for developers and inspired by Google Zanzibar. OpenFGA is vulnerable to a denial of service attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die. Users are advised to upgrade to v1.3.2 and update any offending models. There are no known workarounds for this vulnerability. Note that for models which contained cycles or a relation definition that has the relation itself in its evaluation path, checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. Users who do not have cyclic models are unaffected.","status":"published","published":"2023-09-26T20:58:17.826Z","modified":"2026-10-28T02:31:02.648381886Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T15:44:33.792101Z"},{"id":"GHSA-2hm9-h873-pgqh","title":"OpenFGA Vulnerable to DoS from circular relationship definitions","description":"## Overview\nOpenFGA is vulnerable to a DoS attack when certain Check calls are executed against authorization models that contain circular relationship definitions. When the call is made, it's possible for the server to exhaust resources and die.\n\n## Am I Affected?\nYes, if your store contains an authorization model that allows circular relationships. For example, with this model:\n\n```\nmodel\n  schema 1.1\n\ntype user\n\ntype group\n  relations\n    define memberA: [user] or memberB or memberC or memberD or memberE\n    define memberB: [user] or memberA or memberC or memberD or memberE\n    define memberC: [user] or memberA or memberB or memberD or memberE\n    define memberD: [user] or memberA or memberB or memberC or memberE\n    define memberE: [user] or memberA or memberB or memberC or memberD\n```\n\nThis Check: `(user:anne, memberA, group:X)` can exhaust memory in the server.\n\n## Fix\nUpgrade to v1.3.2 and update any offending models.\n\n  **[BREAKING]** If your model contained cycles or a relation definition that has the relation itself in its evaluation path, then Checks and queries that require evaluation will no longer be evaluated on v1.3.2+ and will return errors instead. You will need to update your models to remove the cycles.","status":"published","published":"2023-09-28T21:27:04Z","modified":"2026-09-10T03:50:03.105890643Z","cvss":[{"version":"3.1","score":5.9,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"medium"}],"cwes":["CWE-835"],"updated_at":"2026-11-02T15:46:34.338541Z"},{"id":"GO-2023-2084","title":"OpenFGA Vulnerable to DoS from circular relationship definitions in github.com/openfga/openfga","description":"OpenFGA Vulnerable to DoS from circular relationship definitions in github.com/openfga/openfga","status":"published","published":"2024-08-21T14:30:18Z","modified":"2026-03-03T04:54:14.83816Z","updated_at":"2026-11-02T15:47:01.185262Z"}]}}