{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-46482","assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","state":"PUBLISHED","assignerShortName":"GitHub_M","dateReserved":"2026-05-14T18:06:06.810Z","datePublished":"2026-08-18T15:44:59.644Z","dateUpdated":"2026-08-18T17:46:31.511Z"},"containers":{"cna":{"title":"MyBB: Security Question insufficient validation","problemTypes":[{"descriptions":[{"cweId":"CWE-636","lang":"en","description":"CWE-636: Not Failing Securely ('Failing Open')","type":"CWE"}]}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"NONE","integrityImpact":"LOW","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"}}],"references":[{"name":"https://github.com/mybb/mybb/security/advisories/GHSA-v2h7-4jp7-j6hh","tags":["x_refsource_CONFIRM"],"url":"https://github.com/mybb/mybb/security/advisories/GHSA-v2h7-4jp7-j6hh"},{"name":"https://github.com/mybb/mybb/commit/bd2a3447939d3084a5926dd66ece04649e0e0d60","tags":["x_refsource_MISC"],"url":"https://github.com/mybb/mybb/commit/bd2a3447939d3084a5926dd66ece04649e0e0d60"},{"name":"https://github.com/mybb/mybb/releases/tag/mybb_1840","tags":["x_refsource_MISC"],"url":"https://github.com/mybb/mybb/releases/tag/mybb_1840"},{"name":"https://mybb.com/versions/1.8.40","tags":["x_refsource_MISC"],"url":"https://mybb.com/versions/1.8.40"}],"affected":[{"vendor":"mybb","product":"mybb","versions":[{"version":"< 1.8.40","status":"affected"}]}],"providerMetadata":{"orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M","dateUpdated":"2026-08-18T15:44:59.644Z"},"descriptions":[{"lang":"en","value":"### Impact\nThe registration component does not validate the text-based _Security Question_ CAPTCHA correctly, allowing attackers to bypass the challenge via a specially crafted value.\n\n\n[CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N](https://www.first.org/cvss/calculator/3.1#CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N)\n\n### Details\nThe public _Registration_ workflow ([`member.php?action=do_register`](https://github.com/mybb/mybb/blob/mybb_1839/member.php#L262-L307)) accepts a hidden field `question_id` — expected to match the question session identifier (`mybb_questionsessions.sid`) — and validates the challenge answer without a fail-closed fallback for invalid identifiers. If the value is blank, forged, or expired, the request continues without a question-related error.\n\n### Patches\nMyBB 1.8.(...) resolves this issue with the following changes:\n\n- Commit: https://github.com/mybb/mybb/commit/\n  - `.patch`: https://github.com/mybb/mybb/commit/.patch\n\n### References\n- Release Notes: https://mybb.com/versions/1.8.(...)/\n\n### For more information\nGo to [mybb.com/security](https://mybb.com/security/) to report possible security concerns or to learn more about security research at MyBB.\n\n### Contact\nThe security team can be reached at [security@mybb.com](mailto:security@mybb.com)."}],"source":{"advisory":"GHSA-v2h7-4jp7-j6hh","discovery":"UNKNOWN"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-18T17:44:40.432629Z","id":"CVE-2026-46482","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-08-18T17:46:31.511Z"}}]}}