CVE-2019-18678: canonical ubuntu_linux HTTP Request/Response Smuggling

Vulnerability summary

CVE-2019-18678 is a medium (CVSS 5.3) HTTP Request/Response Smuggling vulnerability in canonical ubuntu_linux. EPSS estimates a 6.20% chance of exploitation in the next 30 days, higher than 93.4% of scored vulnerabilities.

Timeline

1. 26-11-2019
   PublishedVulnerability first disclosed.
2. 05-08-2024
   Last modifiedVulnerability information updated.

Description

An issue was discovered in Squid 3.x and 4.x through 4.8. It allows attackers to smuggle HTTP requests through frontend software to a Squid instance that splits the HTTP Request pipeline differently. The resulting Response messages corrupt caches (between a client and Squid) with attacker-controlled content at arbitrary URLs. Effects are isolated to software between the attacker client and Squid. There are no effects on Squid itself, nor on any upstream servers. The issue is related to a request header containing whitespace between a header name and a colon.

• CWE-444Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination.