{"id":"CVE-2021-27889","aliases":["EUVD-2021-14626"],"status":"published","description":"Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages.","severity":{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary","from":"nvd"},"epss":{"day":"2026-11-10","score":0.05072,"percentile":0.92398,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":true,"fix_available":false},"cwes":["CWE-79"],"published":"2021-03-15T16:57:02Z","modified":"2026-06-17T03:45:33Z","exploits":[{"source":"exploitdb","id":"EDB-49696","title":"MyBB 1.8.25 - Chained Remote Command Execution","type":"webapps","platform":"php","date":"2021-03-22","url":"https://www.exploit-db.com/exploits/49696"}],"products":[{"vendor":"mybb","product":"mybb"}],"references":[{"url":"https://github.com/mybb/mybb/security/advisories/GHSA-xhj7-3349-mqcm","tags":["x_refsource_MISC","x_transferred","Patch","Third Party Advisory"]},{"url":"http://packetstormsecurity.com/files/161908/MyBB-1.8.25-Remote-Command-Execution.html","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory","VDB Entry"]},{"url":"https://blog.sonarsource.com/mybb-remote-code-execution-chain","tags":["x_refsource_MISC","x_transferred","Exploit","Third Party Advisory"]}],"sources":{"cve":[{"id":"CVE-2021-27889","description":"Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages.","status":"published","published":"2021-03-15T16:57:02Z","modified":"2024-08-03T21:33:17.199Z","updated_at":"2026-11-02T14:33:04.360272Z"}],"euvd":[{"id":"EUVD-2021-14626","description":"Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages.","status":"published","published":"2021-03-15T16:57:02Z","modified":"2024-08-03T21:33:17Z","updated_at":"2026-11-03T03:24:47.80549Z"}],"nvd":[{"id":"CVE-2021-27889","description":"Cross-site Scripting (XSS) vulnerability in MyBB before 1.8.26 via Nested Auto URL when parsing messages.","status":"published","published":"2021-03-15T17:15:22.517Z","modified":"2026-06-17T03:45:33.9Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"primary"},{"version":"2.0","score":4.3,"vector":"AV:N/AC:M/Au:N/C:N/I:P/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:06:50.805771Z"}]}}