GIVE YOUR AGENT THE EVIDENCE

Set up in your agent.

One prompt to get started. Paste it into your coding agent to connect cve.new through MCP and bring vulnerability context into your workflow.

Your agent needs remote MCP support and access to https://cve.new/mcp.

Read the setup guide

GIVE YOUR AGENT THE EVIDENCE

Investigate in your agent.

Turn this advisory into a focused investigation. Ask your agent to check your project’s versions, explain the evidence, and suggest a compatible fix.

Your agent needs remote MCP support and access to https://cve.new/mcp.

Read the setup guide

cve.new
Check your stack
GHSA-mfxh-vp55-7gc6medium5.3

Contao: The registration module re-sends activation mails

Impact

ModuleRegistration::compile() reaches its follow-up registration branch on any POST to a page carrying the module. That branch checks neither FORM_SUBMIT nor the captcha result computed immediately above it, and resendActivationMail() leads to OptInToken::send(), which has no rate limit at all.

Source excerpt · OSV
Applies when

Honest bound. The target must have an unconfirmed registration, that is tl_member.disable = 1 together with an unconfirmed reg- opt-in token. An attacker can create that state for an arbitrary address, since registration requires no ownership proof, but on a site where reg_activate is off the branch is unreachable.

Affected packages

Start with the recorded fix for your release branch. Check your installed version and test compatibility before upgrading. Fixing this advisory does not rule out other vulnerabilities in the release.

contao/core-bundle Packagist
Affected rangeRecorded fix
From 4.1.0 before 5.3.50Ecosystem versions5.3.50
From 5.4.0-RC1 before 5.7.12Ecosystem versions5.7.12

Version evidence: OSV · GHSA-mfxh-vp55-7gc6

View original version evidence (461 explicit versions)

Original source description

ModuleRegistration::compile() reaches its follow-up registration branch on any POST to a page carrying the module. That branch checks neither FORM_SUBMIT nor the captcha result computed immediately above it, and resendActivationMail() leads to OptInToken::send(), which has no rate limit at all.

Impact

Anyone on the internet can make a Contao installation send unlimited mail to an address of their choosing, from the site's own sender and reputation, at one outbound message per HTTP request. That is both a nuisance for the recipient and a deliverability risk for the site operator. The same request is a reliable account oracle for "this address has a pending registration on this site", which is exactly the sort of membership fact a public site is usually expected not to disclose.

Honest bound. The target must have an unconfirmed registration, that is tl_member.disable = 1 together with an unconfirmed reg- opt-in token. An attacker can create that state for an arbitrary address, since registration requires no ownership proof, but on a site where reg_activate is off the branch is unreachable.

References