CVE-2026-46482

{"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` \u2014 expected to match the question session identifier (`mybb_questionsessions.sid`) \u2014 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"}}]}}

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{"affected": [{"affectedData": [{"product": "mybb", "vendor": "mybb", "versions": [{"status": "affected", "version": "< 1.8.40"}]}], "source": "security-advisories@github.com"}], "cveTags": [], "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` \u2014 expected to match the question session identifier (`mybb_questionsessions.sid`) \u2014 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)."}], "id": "CVE-2026-46482", "lastModified": "2026-09-08T21:02:26.047", "metrics": {"cvssMetricV31": [{"cvssData": {"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"}, "exploitabilityScore": 3.9, "impactScore": 1.4, "source": "security-advisories@github.com", "type": "Secondary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-46482", "options": [{"exploitation": "none"}, {"automatable": "yes"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-08-18T17:44:40.432629Z", "version": "2.0.3"}}]}, "published": "2026-08-18T16:17:09.350", "references": [{"source": "security-advisories@github.com", "url": "https://github.com/mybb/mybb/commit/bd2a3447939d3084a5926dd66ece04649e0e0d60"}, {"source": "security-advisories@github.com", "url": "https://github.com/mybb/mybb/releases/tag/mybb_1840"}, {"source": "security-advisories@github.com", "url": "https://github.com/mybb/mybb/security/advisories/GHSA-v2h7-4jp7-j6hh"}, {"source": "security-advisories@github.com", "url": "https://mybb.com/versions/1.8.40"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Deferred", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-636"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,1.8.40)"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "mybb", "source": "cna", "vendor": "mybb"}, "product": "mybb", "vendor": "mybb"}], "created": "2026-08-18T18:00:04.363981+00:00", "updated": "2026-08-18T18:45:03.372023+00:00", "vendors": ["mybb", "mybb$PRODUCT$mybb"]}