Contao vulnerabilities

Contao is an Open Source CMS. From version 4.0.0 until 5.3.50 and 5.7.12, RequestTokenListener validates REQUEST_TOKEN only for POST requests, while the declarative GET guard runs only when an act parameter is present. Backend actions dispatched through the key parameter can therefore execute without a CSRF token when an authenticated backend user loads an attacker-controlled URL. Reachable actions remain limited to modules available to that user, and the advisory demonstrates destructive or state-changing actions rather than privilege escalation. This issue is fixed in versions 5.3.50 and 5.7.12.

Contao is an Open Source CMS. In versions 5.7.0 through 5.7.6, an authenticated backend user who can access one job can request an attachment identifier containing ../ segments and make the job attachment download endpoint read a file from another job directory inside var/job-attachments. The controller authorizes only the jobUuid route parameter. The later attachment lookup joins that authorized job UUID with the attacker-controlled identifier, then passes the combined path to the virtual filesystem. VirtualFilesystem::resolve() canonicalizes the whole path and only rejects paths that escape the filesystem mount, so authorized-job/../victim-job/debug_log.csv becomes victim-job/debug_log.csv. This is a cross-job authorization bypass for known job attachment paths. It is not a practical brute-force against unknown jobs because job directories are UUID v4 values.

Contao is an Open Source CMS. From 5.3.35 through 5.3.47 and from 5.7.0-RC1 through 5.7.8, the Feed Reader front-end module passes configured RSS feed URLs from FeedReaderController::getResponse() to feedIo->read() without scheme or private-address validation, allowing a backend user with module-edit permissions to make the server request internal network services, loopback addresses, or cloud metadata endpoints. In core-bundle/src/Controller/FrontendModule/FeedReaderController.php, the getResponse() function iterates over the configured feed URLs and passes each one directly to the HTTP client (via $this->feedIo->read($url, new Feed())) with no validation, while the DCA field definition for rss_feed in tl_module.php carries no URL scheme or host validation and the HTTP client is wired as @psr18.http_client (Symfony HttpClient) with no SSRF protection configured, since NoPrivateNetworkHttpClient is not used. This issue is fixed in versions 5.3.48.

Contao is an Open Source CMS. In versions 4.13.40 through 5.3.46 and 5.7.0-RC1 through 5.7.6, the crawler leaks auth credentials to external hosts. Contao's crawler tries to prevent confidential HTTP client options from being sent to external domains by creating a scoped client: full options for root page origins, cleaned options for everything else. The cleaner removes Cookie and Authorization headers, but it removes the non-Symfony option names basic_auth and bearer_auth instead of Symfony HttpClient's real auth_basic and auth_bearer options. When contao.crawl.default_http_client_options contains Basic or Bearer authentication for a protected staging/production site, those credentials remain in the "clean" client used for external links or configured additional URIs. An attacker who can get an external URL crawled, for example through a link on a crawled page while the broken-link checker is enabled, can receive the crawler credentials. This issue has been fixed in versions 5.3.47 and 5.7.7.