CVE-2026-107843Medium· 5.3▾ SunlitContao 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 th…
▾ Sunlit zone — Low / medium · no exploitation signal
impact 29.2 · likelihood 0 · exploitation 0
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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.
Refer to the linked advisories for vendor-supplied fixes and affected version ranges.
Affected packages:
contao/core-bundle >= 4.1.0, < 5.3.50contao/core-bundle >= 5.4.0-RC1, < 5.7.12Patched in:
contao/core-bundle 5.3.50contao/core-bundle 5.7.12Connected by shared product, vendor, weakness, or advisory.
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