{"id":"CVE-2024-39912","aliases":["EUVD-2024-2291","GHSA-875x-g8p7-5w27"],"status":"published","title":"Enumeration of valid usernames in web-auth/webauthn-lib","description":"web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-12","score":0.00391,"percentile":0.33684,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-204"],"published":"2024-07-15T16:37:49Z","modified":"2026-10-28T02:30:57Z","fixes":[{"ecosystem":"Packagist","package":"web-auth/webauthn-lib","fixed_in":["4.9.0"],"sources":["ghsa","osv"]},{"ecosystem":"Packagist","package":"web-auth/webauthn-framework","fixed_in":["4.9.0"],"sources":["ghsa","osv"]}],"affected":[{"source":"ghsa","ecosystem":"Packagist","package":"web-auth/webauthn-lib","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.5.0"},{"fixed":"4.9.0"}]}]},{"source":"ghsa","ecosystem":"Packagist","package":"web-auth/webauthn-framework","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.5.0"},{"fixed":"4.9.0"}]}]},{"source":"osv","ecosystem":"Packagist","package":"web-auth/webauthn-lib","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.5.0"},{"fixed":"4.9.0"}]}],"versions":["4.5.0","4.5.1","4.5.2","4.6.0","4.6.1","4.6.2","4.6.3","4.6.4","4.7.0","4.7.1","4.7.2","4.7.3","4.7.4","4.7.5","4.7.6","4.7.7","4.7.8","4.7.9","4.8.0","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.8.7"]},{"source":"osv","ecosystem":"Packagist","package":"web-auth/webauthn-framework","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"4.5.0"},{"fixed":"4.9.0"}]}],"versions":["4.5.0","4.5.1","4.5.2","4.6.0","4.6.1","4.6.2","4.6.3","4.6.4","4.7.0","4.7.1","4.7.2","4.7.3","4.7.4","4.7.5","4.7.6","4.7.7","4.7.8","4.7.9","4.8.0","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.8.7"]}],"products":[{"vendor":"spomky-labs","product":"webauthn_framwork"},{"vendor":"web-auth","product":"webauthn-framework"}],"references":[{"url":"https://github.com/web-auth/webauthn-framework/security/advisories/GHSA-875x-g8p7-5w27","tags":["x_refsource_CONFIRM","x_transferred","advisory","web"]},{"url":"https://github.com/web-auth/webauthn-framework/commit/64de11f6cddc71e56c76e0cc4573bf94d02be045","tags":["x_refsource_MISC","x_transferred","fix","web"]},{"url":"https://github.com/web-auth/webauthn-framework/commit/a9d1352897fba552e659e1445a771dec2d4ed05a","tags":["web"]},{"url":"https://github.com/web-auth/webauthn-lib/commit/b6798de27cdedd8681fe4c9b13ace0ff2456d18b","tags":["web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2024-39912","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-875x-g8p7-5w27"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/39xxx/CVE-2024-39912.json","tags":["advisory"]},{"url":"https://github.com/web-auth/webauthn-framework","tags":["package"]}],"sources":{"cve":[{"id":"CVE-2024-39912","title":"Enumeration of valid usernames in web-auth/webauthn-lib","description":"web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2024-07-15T19:38:04.824Z","modified":"2024-08-02T04:33:11.552Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-204"],"updated_at":"2026-11-02T14:34:19.28149Z"}],"euvd":[{"id":"EUVD-2024-2291","description":"web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2024-07-15T19:38:04Z","modified":"2024-08-02T04:33:11Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T03:50:17.469599Z"}],"ghsa":[{"id":"GHSA-875x-g8p7-5w27","title":"The FIDO2/Webauthn Support for PHP library allows enumeration of valid usernames ","description":"### Summary\n\nThe ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found.\n\n### Details\n\nWhen WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames.\n\n#### Proposal how to resolve it:\n \n```\nreturn $this-\u003epublicKeyCredentialRequestOptionsFactory-\u003ecreate(\n            $this-\u003eprofile,\n            count($allowedCredentials) \u003c= 0 ? self::getRandomCredentials(): $allowedCredentials,\n            $optionsRequest-\u003euserVerification,\n            $extensions\n);\n\nprivate static function getRandomCredentials(): array\n{\n        $credentialSources = [];\n        for ($i = 0; $i \u003c= rand(0,1); $i++) {\n            $credentialSources[] = new PublicKeyCredentialSource(\n                random_bytes(32),\n                \"public-key\",\n                [],\n                \"basic\",\n                new EmptyTrustPath(),\n                Uuid::v7(),\n                random_bytes(77),\n                Uuid::v7()-\u003e__toString(),\n                rand(0, 6000),\n                null\n            );\n        }\n        return array_map(\n            static fn (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor =\u003e $credential-\u003egetPublicKeyCredentialDescriptor(),\n            $credentialSources\n        );\n}\n```\n\n### PoC\n\ncurl https://example.com/assertion/options \\\n  -H 'content-type: application/json' \\\n  --data-raw '{\"username\":\"NotMeRandomUsername123\"}'\n\n### Impact\n\nBy knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks.\n","status":"published","published":"2024-07-15T16:37:49Z","modified":"2024-08-04T05:03:38Z","cvss":[{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-204"],"updated_at":"2026-11-02T14:37:57.422393Z"}],"nvd":[{"id":"CVE-2024-39912","description":"web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2024-07-15T20:15:03.693Z","modified":"2026-06-17T07:43:00.86Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-204"],"updated_at":"2026-11-02T14:10:12.994089Z"}],"osv":[{"id":"CVE-2024-39912","title":"Enumeration of valid usernames in web-auth/webauthn-lib","description":"web-auth/webauthn-lib is an open source set of PHP libraries and a Symfony bundle to allow developers to integrate that authentication mechanism into their web applications. The ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found. When WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames. By knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks. This issue has been addressed in version 4.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.","status":"published","published":"2024-07-15T19:38:04.824Z","modified":"2026-10-28T02:30:57.70420788Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"cwes":["CWE-204"],"updated_at":"2026-11-02T15:44:41.618074Z"},{"id":"GHSA-875x-g8p7-5w27","title":"The FIDO2/Webauthn Support for PHP library allows enumeration of valid usernames ","description":"### Summary\n\nThe ProfileBasedRequestOptionsBuilder method returns allowedCredentials without any credentials if no username was found.\n\n### Details\n\nWhen WebAuthn is used as the first or only authentication method, an attacker can enumerate usernames based on the absence of the `allowedCredentials` property in the assertion options response. This allows enumeration of valid or invalid usernames.\n\n#### Proposal how to resolve it:\n \n```\nreturn $this-\u003epublicKeyCredentialRequestOptionsFactory-\u003ecreate(\n            $this-\u003eprofile,\n            count($allowedCredentials) \u003c= 0 ? self::getRandomCredentials(): $allowedCredentials,\n            $optionsRequest-\u003euserVerification,\n            $extensions\n);\n\nprivate static function getRandomCredentials(): array\n{\n        $credentialSources = [];\n        for ($i = 0; $i \u003c= rand(0,1); $i++) {\n            $credentialSources[] = new PublicKeyCredentialSource(\n                random_bytes(32),\n                \"public-key\",\n                [],\n                \"basic\",\n                new EmptyTrustPath(),\n                Uuid::v7(),\n                random_bytes(77),\n                Uuid::v7()-\u003e__toString(),\n                rand(0, 6000),\n                null\n            );\n        }\n        return array_map(\n            static fn (PublicKeyCredentialSource $credential): PublicKeyCredentialDescriptor =\u003e $credential-\u003egetPublicKeyCredentialDescriptor(),\n            $credentialSources\n        );\n}\n```\n\n### PoC\n\ncurl https://example.com/assertion/options \\\n  -H 'content-type: application/json' \\\n  --data-raw '{\"username\":\"NotMeRandomUsername123\"}'\n\n### Impact\n\nBy knowing which usernames are valid, attackers can focus their efforts on a smaller set of potential targets, increasing the efficiency and likelihood of successful attacks.\n","status":"published","published":"2024-07-15T16:37:49Z","modified":"2026-09-10T03:50:16.366617002Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"},{"version":"4.0","score":6.9,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N","level":"medium"}],"cwes":["CWE-204"],"updated_at":"2026-11-02T15:46:42.077781Z"}]}}