#VU55501 Inconsistent interpretation of HTTP requests in Varnish Cache - CVE-2021-36740
Published: August 2, 2021
Vulnerability identifier: #VU55501
Vulnerability risk: Medium
CVSSv4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green
CVE-ID: CVE-2021-36740
CWE-ID: CWE-444
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerable software:
Varnish Cache
Varnish Cache
Software vendor:
Varnish Software
Varnish Software
Description
The vulnerability allows a remote attacker to preform HTTP request smuggling attacks.
The vulnerability exists due to improper validation of HTTP/2 requests. A remote attacker can send a specially crafted HTTP/2 POST request with a large Content-Length header to the server and smuggle arbitrary HTTP headers.
Successful exploitation of vulnerability may allow an attacker to poison HTTP cache or bypass VCL authorization.
Remediation
Install updates from vendor's website.