CVE-2024-29371 is a vulnerability identified in the jose4j Java library, specifically in versions prior to 0.9.6. The flaw arises from the way the library handles JSON Web Encryption (JWE) tokens that are compressed before encryption. An attacker can craft a malicious JWE token with an exceptionally high compression ratio, which when processed by the vulnerable jose4j implementation, causes excessive memory allocation and prolonged processing time during decompression. This leads to a Denial-of-Service (DoS) condition by exhausting server resources, thereby impacting the availability of services relying on this library. The vulnerability does not affect confidentiality or integrity of data, as it does not allow unauthorized data access or modification. It can be exploited remotely without requiring authentication or user interaction, increasing its risk profile. The CVSS v3.1 base score is 7.5, reflecting high severity due to network attack vector, low attack complexity, no privileges required, no user interaction, and a significant impact on availability. The vulnerability is categorized under CWE-1259, which relates to resource exhaustion through decompression bombs or similar techniques. No public exploits have been reported yet, but the nature of the flaw makes it a plausible target for attackers aiming to disrupt services. The lack of a patch link suggests that users should upgrade to jose4j version 0.9.6 or later where the issue is resolved. Organizations using jose4j for handling JWE tokens in authentication, authorization, or secure messaging should prioritize remediation to prevent potential DoS attacks.

For European organizations, the primary impact of CVE-2024-29371 is service disruption due to Denial-of-Service attacks. Applications that rely on jose4j for processing JWE tokens—commonly used in secure communications, identity management, and API security—may become unresponsive or crash under attack. This can lead to downtime, loss of business continuity, and degraded user experience. Critical infrastructure or services that depend on these applications could face operational interruptions. Since the vulnerability does not compromise confidentiality or integrity, data breaches are unlikely; however, the availability impact alone can have severe consequences, especially for sectors requiring high uptime such as finance, healthcare, and government services. The ease of exploitation without authentication or user interaction increases the risk of automated attacks targeting exposed endpoints. Additionally, the increased resource consumption could lead to cascading failures in shared hosting or cloud environments, amplifying the impact. European organizations must consider the risk to their service availability and potential reputational damage from prolonged outages.

To mitigate CVE-2024-29371, organizations should immediately upgrade the jose4j library to version 0.9.6 or later, where the vulnerability is fixed. If upgrading is not immediately feasible, implement strict input validation to detect and reject JWE tokens with suspiciously high compression ratios or abnormal sizes before decompression. Employ resource usage limits such as memory and CPU time quotas on processes handling JWE tokens to prevent resource exhaustion. Deploy Web Application Firewalls (WAFs) or API gateways with anomaly detection capabilities to identify and block malformed or malicious tokens. Monitor application logs and system metrics for unusual spikes in resource consumption that could indicate exploitation attempts. Additionally, consider rate limiting requests to endpoints that process JWE tokens to reduce the risk of DoS attacks. Conduct regular security assessments and penetration testing focusing on token processing components. Finally, maintain an incident response plan to quickly address potential DoS incidents related to this vulnerability.