Webcache Poisoning in Symfony
CVE-2021-41267

6.5MEDIUM

Key Information:

Vendor
Symfony
Status
Symfony
Vendor
CVE Published:
24 November 2021

Summary

Symfony/Http-Kernel is the HTTP kernel component for Symfony, a PHP framework for web and console applications and a set of reusable PHP components. Headers that are not part of the "trusted_headers" allowed list are ignored and protect users from "Cache poisoning" attacks. In Symfony 5.2, maintainers added support for the X-Forwarded-Prefix headers, but this header was accessible in SubRequest, even if it was not part of the "trusted_headers" allowed list. An attacker could leverage this opportunity to forge requests containing a X-Forwarded-Prefix header, leading to a web cache poisoning issue. Versions 5.3.12 and later have a patch to ensure that the X-Forwarded-Prefix header is not forwarded to subrequests when it is not trusted.

Affected Version(s)

symfony >= 5.2.0, < 5.3.12

References

https://github.com/symfony/symfony/pull/44243
x_refsource_MISC
https://github.com/symfony/symfony/releases/tag/v5.3.12
x_refsource_MISC
https://github.com/symfony/symfony/security/advisories/GH...
x_refsource_CONFIRM

CVSS V3.1

Score:
6.5
Severity:
MEDIUM
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
Required
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.