{"id":"CVE-2026-49952","aliases":["EUVD-2026-36792","GHSA-mx47-h32c-x878"],"status":"published","title":"Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle","description":"Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.","severity":{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.04717,"percentile":0.91906,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":false},"cwes":["CWE-323"],"published":"2026-06-15T18:43:21Z","modified":"2026-10-25T23:10:00Z","exploits":[{"source":"exploitdb","id":"EDB-52621","title":"Discuz! X5.0 - Authentication Bypass","type":"webapps","platform":"multiple","date":"2026-07-07","url":"https://www.exploit-db.com/exploits/52621"},{"source":"nuclei","id":"CVE-2026-49952","title":"Discuz! X5.0 - Authentication Bypass","type":"detection template","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-49952.yaml"},{"source":"pocgithub","id":"CerberusMrXi/Discuz-X5.0-Authentication-Bypass-Exploit-Framework","title":"CerberusMrXi/Discuz-X5.0-Authentication-Bypass-Exploit-Framework","date":"2026-07-24","url":"https://github.com/CerberusMrXi/Discuz-X5.0-Authentication-Bypass-Exploit-Framework"},{"source":"pocgithub","id":"passwa11/CVE-2026-49952","title":"passwa11/CVE-2026-49952","date":"2026-06-17","url":"https://github.com/passwa11/CVE-2026-49952"}],"products":[{"vendor":"discuz!","product":"discuz! x5.0"}],"references":[{"url":"https://karmainsecurity.com/KIS-2026-09","tags":["technical-description"]},{"url":"https://karmainsecurity.com/chaining-bugs-in-discuz-from-race-condition-to-rce","tags":["exploit"]},{"url":"https://gitee.com/Discuz/DiscuzX/commit/9962dad52c4c6999dabaf91ecd70377c680ff3c6","tags":["patch"]},{"url":"https://www.vulncheck.com/advisories/discuz-x5-0-authentication-bypass-via-dbbak-php-encryption-oracle","tags":["third-party-advisory"]},{"url":"http://seclists.org/fulldisclosure/2026/Jun/3"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-49952"},{"url":"https://github.com/advisories/GHSA-mx47-h32c-x878"}],"sources":{"cve":[{"id":"CVE-2026-49952","title":"Discuz! X5.0 Authentication Bypass via dbbak.php Encryption Oracle","description":"Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.","status":"published","published":"2026-06-15T18:43:21.99Z","modified":"2026-07-28T01:49:38.302Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical","assessor":"cna"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"cna"}],"cwes":["CWE-323"],"updated_at":"2026-11-02T13:35:10.963527Z"}],"euvd":[{"id":"EUVD-2026-36792","description":"Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.","status":"published","published":"2026-06-15T18:43:21Z","modified":"2026-07-28T01:49:38Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N","level":"critical"}],"updated_at":"2026-11-02T18:02:32.258903Z"}],"ghsa":[{"id":"GHSA-mx47-h32c-x878","title":"Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability...","description":"Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.","status":"published","published":"2026-06-15T21:30:40Z","modified":"2026-06-16T12:32:01Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical"}],"cwes":["CWE-323"],"updated_at":"2026-11-02T15:08:48.16867Z"}],"nvd":[{"id":"CVE-2026-49952","description":"Discuz! X5.0 releases 20260320 through 20260501 contains an authentication bypass vulnerability that allows unauthenticated remote attackers to gain unauthorized access to database backup and restore functionality by exploiting a shared cryptographic key between UCenter integration and the database backup API exposed by dbbak.php. Attackers can inject a crafted payload through the username parameter during login to abuse the encryption oracle in logging_ctl::logging_more(), obtain a legitimately signed token, and use it to bypass authorization for database export and import operations, with the additional ability to trigger a race condition to impersonate arbitrary users.","status":"published","published":"2026-06-15T20:16:29.103Z","modified":"2026-10-25T23:10:00.167Z","cvss":[{"version":"4.0","score":9.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"critical","assessor":"secondary"},{"version":"3.1","score":9.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","level":"critical","assessor":"secondary"}],"cwes":["CWE-323"],"updated_at":"2026-11-02T14:12:23.846948Z"}]}}