Ruby cgi.rb response splitting

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.


A vulnerability was found in Ruby. It has been rated as critical. This issue affects some unknown processing of the file cgi.rb. The manipulation leads to http response splitting. The CWE definition for the vulnerability is CWE-443. The weakness was presented 11/23/2022. The advisory is shared at The identification of this vulnerability is CVE-2021-33621. The attack may be initiated remotely. Technical details are available. Furthermore, there is an exploit available. The exploit has been disclosed to the public and may be used. The price for an exploit might be around USD $0-$5k at the moment. It is declared as proof-of-concept. The exploit is available at We expect the 0-day to have been worth approximately $0-$5k. It is recommended to upgrade the affected component. A possible mitigation has been published even before and not after the disclosure of the vulnerability. [Details]

IOB - Indicator of Behavior (217)


IOC - Indicator of Compromise (7)

These indicators of compromise highlight associated network ranges which are known to be part of research and attack activities.

IDIP rangeActorTypeConfidence StealerpredictiveHigh XxxxxxxpredictiveHigh XxxxxxxpredictiveHigh
4xxx.xx.xx.xXxxxxxx XxxxxxxpredictiveHigh XxxxxxxpredictiveHigh XxxxxxxpredictiveHigh XxxxxxxpredictiveHigh

IOA - Indicator of Attack (1)

These indicators of attack list the potential fragments used for technical activities like reconnaissance, exploitation, privilege escalation, and exfiltration. This data is unique as it uses our predictive model for actor profiling.


Are you interested in using VulDB?

Download the whitepaper to learn more about our service!