CVE-2020-15810: XSS
An issue was discovered in Squid before 4.13 and 5.x before 5.0.4. Due to incorrect data validation, HTTP Request Smuggling attacks may succeed against HTTP and HTTPS traffic. This leads to cache poisoning. This allows any client, including browser scripts, to bypass local security and poison the proxy cache and any downstream caches with content from an arbitrary source. When configured for relaxed header parsing (the default), Squid relays headers containing whitespace characters to upstream servers. When this occurs as a prefix to a Content-Length header, the frame length specified will be ignored by Squid (allowing for a conflicting length to be used from another Content-Length header) but relayed upstream.
Other sources
Squid-Cache Squid is vulnerable to HTTP request smuggling, caused by improper input validation. By sending specially crafted HTTP(S) request messages, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.
— IBM
Affected Software
Remediation
Event History
Frequently Asked Questions
What is the vulnerability ID for this Squid-Cache vulnerability?
The vulnerability ID for this Squid-Cache vulnerability is CVE-2020-15810.
What is the severity of CVE-2020-15810?
CVE-2020-15810 has a severity rating of 9.6 (Critical).
What is the affected software for CVE-2020-15810?
The affected software for CVE-2020-15810 includes Squid versions before 4.13 and 5.x before 5.0.4, as well as IBM Security Guardium versions up to 11.3.
How does CVE-2020-15810 impact HTTP and HTTPS traffic?
CVE-2020-15810 can lead to successful HTTP Request Smuggling attacks against HTTP and HTTPS traffic, resulting in cache poisoning.
Where can I find more information about CVE-2020-15810?
You can find more information about CVE-2020-15810 in the following references: [1](http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00012.html), [2](http://lists.opensuse.org/opensuse-security-announce/2020-09/msg00017.html), [3](https://github.com/squid-cache/squid/security/advisories/GHSA-3365-q9qx-f98m).