Inconsistent interpretation of HTTP requests in http-kernel - CVE-2021-41267

Vulnerability details

The vulnerability allows a remote attacker to preform HTTP request smuggling attacks.

The vulnerability exists due to improper validation of HTTP requests. A remote attacker can send a specially crafted HTTP request to the server and smuggle arbitrary HTTP headers.

Successful exploitation of vulnerability may allow an attacker to poison HTTP cache and perform phishing attacks.

Affected software

How to mitigate CVE-2021-41267

External References

• https://github.com/symfony/symfony/security/advisories/GHSA-q3j3-w37x-hq2q
• https://github.com/symfony/symfony/releases/tag/v5.3.12
• https://github.com/symfony/symfony/commit/95dcf51682029e89450aee86267e3d553aa7c487
• https://github.com/symfony/symfony/pull/44243

Related Security Bulletins

• Inconsistent interpretation of HTTP requests in Symfony http-kernel
• Multiple vulnerabilities in Symfony
• Webcache poisoning via X-Forwarded-Prefix and sub-request in Shopware