Response Splitting attack in the HTTP server of WEBrick (CVE-2017-17742).
Delete directory using symlink when decompressing tar (CVE-2019-8320).
Escape sequence injection vulnerability in verbose (CVE-2019-8321).
Escape sequence injection vulnerability in gem owner (CVE-2019-8322).
Escape sequence injection vulnerability in API response handling (CVE-2019-8323).
Installing a malicious gem may lead to arbitrary code execution (CVE-2019-8324).
Escape sequence injection vulnerability in errors (CVE-2019-8325).
Regular Expression Denial of Service vulnerability of WEBrick's Digest access authentication (CVE-2019-16201).
HTTP Response Splitting attack in the HTTP server of WEBrick (CVE-2019-16254).
Code injection vulnerability (CVE-2019-16255).
A potential HTTP request smuggling vulnerability in WEBrick was reported. WEBrick (bundled along with jruby) was too tolerant against an invalid Transfer-Encoding header. This may lead to inconsistent interpretation between WEBrick and some HTTP proxy servers, which may allow the attacker to "smuggle" a request (CVE-2020-25613).