{"api_version":"1","generated_at":"2026-10-09T21:33:01+00:00","cve":"CVE-2026-107843","urls":{"html":"https://cve.report/CVE-2026-107843","api":"https://cve.report/api/cve/CVE-2026-107843.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-107843","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-107843"},"summary":{"title":"Contao: The registration module re-sends activation mails on any unauthenticated POST, with no throttle and no captcha check","description":"Contao is an Open Source CMS. From version 4.1.0 until 5.3.50 and 5.7.12, ModuleRegistration::compile() enters its follow-up registration branch on any POST to a page containing the registration module without verifying FORM_SUBMIT or the preceding captcha result. resendActivationMail() can then invoke OptInToken::send() without rate limiting, allowing an unauthenticated attacker to cause repeated activation emails to be sent to an address with a pending registration and to determine whether that pending registration exists. The branch is reachable only when reg_activate is enabled and the target has an unconfirmed registration and opt-in token. This issue is fixed in versions 5.3.50 and 5.7.12.","state":"PUBLISHED","assigner":"GitHub_M","published_at":"2026-10-09 20:17:10","updated_at":"2026-10-09 20:17:10"},"problem_types":["CWE-204","CWE-770","CWE-204 CWE-204: Observable Response Discrepancy","CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling"],"metrics":[{"version":"3.1","source":"security-advisories@github.com","type":"Secondary","score":"5.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"5.3","severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"}}],"references":[{"url":"https://github.com/contao/contao/commit/2ea6117f9049db7221679251cfc41e67d941a74b","name":"https://github.com/contao/contao/commit/2ea6117f9049db7221679251cfc41e67d941a74b","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/contao/contao/security/advisories/GHSA-mfxh-vp55-7gc6","name":"https://github.com/contao/contao/security/advisories/GHSA-mfxh-vp55-7gc6","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/contao/contao/releases/tag/5.7.12","name":"https://github.com/contao/contao/releases/tag/5.7.12","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://github.com/contao/contao/releases/tag/5.3.50","name":"https://github.com/contao/contao/releases/tag/5.3.50","refsource":"security-advisories@github.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-107843","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-107843","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"contao","product":"contao","version":"affected >= 4.1.0, < 5.3.50","platforms":[]},{"source":"CNA","vendor":"contao","product":"contao","version":"affected >= 5.4.0-RC1, < 5.7.12","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":null,"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"product":"contao","vendor":"contao","versions":[{"status":"affected","version":">= 4.1.0, < 5.3.50"},{"status":"affected","version":">= 5.4.0-RC1, < 5.7.12"}]}],"descriptions":[{"lang":"en","value":"Contao is an Open Source CMS. From version 4.1.0 until 5.3.50 and 5.7.12, ModuleRegistration::compile() enters its follow-up registration branch on any POST to a page containing the registration module without verifying FORM_SUBMIT or the preceding captcha result. resendActivationMail() can then invoke OptInToken::send() without rate limiting, allowing an unauthenticated attacker to cause repeated activation emails to be sent to an address with a pending registration and to determine whether that pending registration exists. The branch is reachable only when reg_activate is enabled and the target has an unconfirmed registration and opt-in token. This issue is fixed in versions 5.3.50 and 5.7.12."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"NONE","baseScore":5.3,"baseSeverity":"MEDIUM","confidentialityImpact":"LOW","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","version":"3.1"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-204","description":"CWE-204: Observable Response Discrepancy","lang":"en","type":"CWE"}]},{"descriptions":[{"cweId":"CWE-770","description":"CWE-770: Allocation of Resources Without Limits or Throttling","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-10-09T19:21:32.011Z","orgId":"a0819718-46f1-4df5-94e2-005712e83aaa","shortName":"GitHub_M"},"references":[{"name":"https://github.com/contao/contao/security/advisories/GHSA-mfxh-vp55-7gc6","tags":["x_refsource_CONFIRM"],"url":"https://github.com/contao/contao/security/advisories/GHSA-mfxh-vp55-7gc6"},{"name":"https://github.com/contao/contao/commit/2ea6117f9049db7221679251cfc41e67d941a74b","tags":["x_refsource_MISC"],"url":"https://github.com/contao/contao/commit/2ea6117f9049db7221679251cfc41e67d941a74b"},{"name":"https://github.com/contao/contao/releases/tag/5.3.50","tags":["x_refsource_MISC"],"url":"https://github.com/contao/contao/releases/tag/5.3.50"},{"name":"https://github.com/contao/contao/releases/tag/5.7.12","tags":["x_refsource_MISC"],"url":"https://github.com/contao/contao/releases/tag/5.7.12"}],"source":{"advisory":"GHSA-mfxh-vp55-7gc6","discovery":"UNKNOWN"},"title":"Contao: The registration module re-sends activation mails on any unauthenticated POST, with no throttle and no captcha check"}},"cveMetadata":{"assignerOrgId":"a0819718-46f1-4df5-94e2-005712e83aaa","assignerShortName":"GitHub_M","cveId":"CVE-2026-107843","datePublished":"2026-10-09T19:21:32.011Z","dateReserved":"2026-10-08T22:34:49.291Z","dateUpdated":"2026-10-09T19:21:32.011Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-10-09 20:17:10","lastModifiedDate":"2026-10-09 20:17:10","problem_types":["CWE-204","CWE-770","CWE-204 CWE-204: Observable Response Discrepancy","CWE-770 CWE-770: Allocation of Resources Without Limits or Throttling"],"metrics":{"cvssMetricV31":[{"source":"security-advisories@github.com","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","baseScore":5.3,"baseSeverity":"MEDIUM","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"LOW","integrityImpact":"NONE","availabilityImpact":"NONE"},"exploitabilityScore":3.9,"impactScore":1.4}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"107843","Ordinal":"1","Title":"Contao: The registration module re-sends activation mails on any","CVE":"CVE-2026-107843","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"107843","Ordinal":"1","NoteData":"Contao is an Open Source CMS. From version 4.1.0 until 5.3.50 and 5.7.12, ModuleRegistration::compile() enters its follow-up registration branch on any POST to a page containing the registration module without verifying FORM_SUBMIT or the preceding captcha result. resendActivationMail() can then invoke OptInToken::send() without rate limiting, allowing an unauthenticated attacker to cause repeated activation emails to be sent to an address with a pending registration and to determine whether that pending registration exists. The branch is reachable only when reg_activate is enabled and the target has an unconfirmed registration and opt-in token. This issue is fixed in versions 5.3.50 and 5.7.12.","Type":"Description","Title":"Contao: The registration module re-sends activation mails on any"}]}}}