Symfony is a PHP framework for web and console applications and a set of reusable PHP components. Starting in versions 2.0.0, 5.0.0, and 6.0.0 and prior to versions 4.4.51, 5.4.31, and 6.3.8, some Twig filters in CodeExtension use `is_safe=html` but don't actually ensure their input is safe. As of versions 4.4.51, 5.4.31, and 6.3.8, Symfony now escapes the output of the affected filters.

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. When authenticating users Symfony by default regenerates the session ID upon login, but preserves the rest of session attributes. Because this does not clear CSRF tokens upon login, this might enables same-site attackers to bypass the CSRF protection mechanism by performing an attack similar to a session-fixation. This issue has been fixed in the 4.4 branch.

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. The Symfony HTTP cache system, acts as a reverse proxy: It caches entire responses (including headers) and returns them to the clients. In a recent change in the `AbstractSessionListener`, the response might contain a `Set-Cookie` header. If the Symfony HTTP cache system is enabled, this response might bill stored and return to the next clients. An attacker can use this vulnerability to retrieve the victim's session. This issue has been patched and is available for branch 4.4.

Symfony is a PHP framework for web and console applications and a set of reusable PHP components. The Symfony form component provides a CSRF protection mechanism by using a random token injected in the form and using the session to store and control the token submitted by the user. When using the FrameworkBundle, this protection can be enabled or disabled with the configuration. If the configuration is not specified, by default, the mechanism is enabled as long as the session is enabled. In a recent change in the way the configuration is loaded, the default behavior has been dropped and, as a result, the CSRF protection is not enabled in form when not explicitly enabled, which makes the application sensible to CSRF attacks. This issue has been resolved in the patch versions listed and users are advised to update. There are no known workarounds for this issue.

The debug handler in Symfony before v2.7.33, 2.8.x before v2.8.26, 3.x before v3.2.13, and 3.3.x before v3.3.6 has XSS via an array key during exception pretty printing in ExceptionHandler.php, as demonstrated by a /_debugbar/open?op=get URI. NOTE: the vendor's position is that this is not a vulnerability because the debug tools are not intended for production use. NOTE: the Symfony Debug component is used by Laravel Debugbar

The attemptAuthentication function in Component/Security/Http/Firewall/UsernamePasswordFormAuthenticationListener.php in Symfony before 2.3.41, 2.7.x before 2.7.13, 2.8.x before 2.8.6, and 3.0.x before 3.0.6 does not limit the length of a username stored in a session, which allows remote attackers to cause a denial of service (session storage consumption) via a series of authentication attempts with long, non-existent usernames.

The nextBytes function in the SecureRandom class in Symfony before 2.3.37, 2.6.x before 2.6.13, and 2.7.x before 2.7.9 does not properly generate random numbers when used with PHP 5.x without the paragonie/random_compat library and the openssl_random_pseudo_bytes function fails, which makes it easier for attackers to defeat cryptographic protection mechanisms via unspecified vectors.

Symfony 2.3.x before 2.3.35, 2.6.x before 2.6.12, and 2.7.x before 2.7.7 might allow remote attackers to have unspecified impact via a timing attack involving the (1) Symfony/Component/Security/Http/RememberMe/PersistentTokenBasedRememberMeServices or (2) Symfony/Component/Security/Http/Firewall/DigestAuthenticationListener class in the Symfony Security Component, or (3) legacy CSRF implementation from the Symfony/Component/Form/Extension/Csrf/CsrfProvider/DefaultCsrfProvider class in the Symfony Form component.

Session fixation vulnerability in the "Remember Me" login feature in Symfony 2.3.x before 2.3.35, 2.6.x before 2.6.12, and 2.7.x before 2.7.7 allows remote attackers to hijack web sessions via a session id.