CVE-2023-29479 identifies a vulnerability in Ribose RNP, an open-source implementation of the OpenPGP standard used for encryption and signing. Versions prior to 0.16.3 may hang or become unresponsive when processing malformed input data. This behavior corresponds to a denial-of-service (DoS) condition categorized under CWE-770 (Allocation of Resources Without Limits or Throttling). The vulnerability can be triggered remotely without authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L). The impact is limited to availability, with no confidentiality or integrity compromise. The vulnerability arises due to insufficient input validation or resource management when handling malformed packets or messages, causing the software to enter a hung state. Ribose RNP is commonly integrated into cryptographic tools and libraries, meaning that any dependent applications could inherit this vulnerability. Although no known exploits have been reported in the wild, the medium CVSS score of 5.3 reflects the potential for service disruption. No explicit patches are linked in the provided data, but upgrading to version 0.16.3 or later is recommended to address the issue. This vulnerability highlights the importance of robust input validation and resource management in cryptographic software to prevent denial-of-service conditions.

For European organizations, the primary impact of CVE-2023-29479 is the potential disruption of services relying on Ribose RNP for cryptographic operations such as encryption, decryption, and signing. This could affect secure communications, email encryption, software package signing, and other security-critical workflows. Denial-of-service conditions may lead to temporary unavailability of these services, impacting business continuity and operational efficiency. Organizations in sectors such as finance, government, healthcare, and critical infrastructure that depend on secure messaging and data protection could experience interruptions. While the vulnerability does not expose sensitive data or allow unauthorized access, the loss of availability can degrade trust in security systems and potentially delay critical operations. Additionally, if attackers combine this DoS with other attack vectors, it could facilitate broader disruption. Given the remote exploitability without authentication, attackers could target exposed services or interfaces that process OpenPGP data. The lack of known exploits reduces immediate risk, but proactive mitigation is essential to prevent future exploitation.

1. Upgrade Ribose RNP to version 0.16.3 or later as soon as the patch is available to ensure the vulnerability is addressed. 2. Implement strict input validation and sanitization on all data processed by Ribose RNP or dependent applications to detect and reject malformed inputs before processing. 3. Employ resource limiting and timeout mechanisms to prevent the software from hanging indefinitely when encountering unexpected input. 4. Monitor logs and network traffic for unusual patterns indicative of malformed OpenPGP packets or repeated attempts to trigger the hang condition. 5. Isolate critical cryptographic services behind firewalls and restrict access to trusted sources to reduce exposure to remote attacks. 6. Conduct regular security assessments and fuzz testing on cryptographic components to identify and remediate similar resource exhaustion issues. 7. Maintain an incident response plan that includes procedures for handling denial-of-service conditions affecting cryptographic services. 8. Engage with Ribose RNP maintainers and community to stay informed about patches, advisories, and best practices.