Security Bulletin: CVE-2019-17569, CVE-2020-1935 HTTP Request Smuggling if Tomcat was located behind a reverse proxy

Summary

In Apache Tomcat 9.0.0.M1 to 9.0.30, 8.5.0 to 8.5.50 and 7.0.0 to 7.0.99 the HTTP header parsing code used an approach to end-of-line parsing that allowed some invalid HTTP headers to be parsed as valid. This led to a possibility of HTTP Request Smuggling if Tomcat was located behind a reverse proxy that incorrectly handled the invalid Transfer-Encoding header in a particular manner. Such a reverse proxy is considered unlikely.

Vulnerability Details

CVEID:CVE-2020-1935
**DESCRIPTION:**Apache Tomcat is vulnerable to HTTP request smuggling, caused by a flaw when handling unusual Transfer-Encoding HTTP header. By sending a specially-crafted request, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.
CVSS Base score: 6.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/176788 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)

CVEID:CVE-2019-17569
**DESCRIPTION:**Apache Tomcat is vulnerable to HTTP request smuggling, caused by a flaw when handling unusual Transfer-Encoding HTTP header. By sending a specially-crafted request, an attacker could exploit this vulnerability to poison the web cache, bypass web application firewall protection, and conduct XSS attacks.
CVSS Base score: 6.5
CVSS Temporal Score: See: https://exchange.xforce.ibmcloud.com/vulnerabilities/176784 for the current score.
CVSS Vector: (CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N)

Affected Products and Versions

Remediation/Fixes

Upgrade to 6.1.7.9, 7.0.5.4, 7.1.1.0 or later.

Workarounds and Mitigations

None