CVE-2024-5193 identifies a CRLF (Carriage Return Line Feed) injection vulnerability in Ritlabs TinyWeb Server version 1.94, specifically within the Request Handler component. The vulnerability arises when an attacker manipulates input containing %0D%0A (encoded CRLF characters), which the server improperly processes, allowing injection of CRLF sequences into HTTP responses. This flaw enables HTTP response splitting attacks, where an attacker can craft malicious HTTP headers or responses, potentially leading to cache poisoning, cross-site scripting (XSS), or other injection-based attacks that compromise the integrity and security of web communications. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. Although no known exploits are currently reported in the wild, public disclosure of the exploit code increases the likelihood of exploitation attempts. The vendor has released TinyWeb Server version 1.99, which includes a patch identified by commit d49c3da6a97e950975b18626878f3ee1f082358e, to remediate the vulnerability. The vendor did not respond to early disclosure communications, which may delay coordinated mitigation efforts. The CVSS 4.0 vector (AV:N/AC:L/AT:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P) reflects a medium severity rating with network attack vector, low attack complexity, no privileges or user interaction required, and limited impact on integrity.

For European organizations, this vulnerability poses a moderate risk primarily to web services relying on Ritlabs TinyWeb Server 1.94. Successful exploitation could allow attackers to manipulate HTTP responses, leading to cache poisoning or injection of malicious scripts, which can compromise user data confidentiality and integrity. This may result in session hijacking, phishing, or distribution of malware via trusted domains. Organizations operating critical infrastructure or handling sensitive data could face reputational damage and regulatory scrutiny under GDPR if user data is compromised. The ease of remote exploitation without authentication increases the threat landscape, especially for publicly accessible web servers. However, the absence of known active exploits reduces immediate risk, though the public availability of exploit code necessitates prompt action. The impact on availability is minimal, but the integrity and confidentiality risks warrant attention.

European organizations should immediately upgrade Ritlabs TinyWeb Server from version 1.94 to version 1.99 or later, which contains the official patch for CVE-2024-5193. Until the upgrade is applied, network-level mitigations such as Web Application Firewalls (WAFs) should be configured to detect and block HTTP requests containing suspicious CRLF injection patterns (%0D%0A sequences). Security teams should audit server logs for unusual HTTP header manipulations or anomalies indicative of exploitation attempts. Implement strict input validation and sanitization on all user-supplied data processed by the web server. Additionally, organizations should monitor threat intelligence feeds for emerging exploit activity related to this vulnerability. For critical environments, consider isolating affected servers behind reverse proxies that can enforce header integrity. Finally, ensure incident response plans include procedures for CRLF injection and HTTP response splitting scenarios.