CVE-2022-29161 identifies a cryptographic vulnerability in the XWiki Platform, a widely used generic wiki platform that provides runtime services for applications built on top of it. The vulnerability stems from the XWiki Crypto API's default use of SHA-1 with RSA for signing X.509 certificates. SHA-1 is a deprecated cryptographic hash function due to its susceptibility to collision attacks, where two different inputs produce the same hash output. This weakness undermines the integrity and trustworthiness of digital certificates, potentially allowing attackers to forge certificates or impersonate legitimate services. The vulnerability affects multiple versions of XWiki Platform prior to 13.10.6, versions from 14.0.0 up to but not including 14.3.1, and versions from 14.4.0 up to but not including 14.4-rc-1. The issue has been addressed in patched versions 13.10.6, 14.3.1, and 14.4-rc-1, where the Crypto API now defaults to using SHA-256 with RSA for certificate signatures, a significantly more secure algorithm resistant to collision attacks. For organizations unable to upgrade immediately, a local patch can be applied to the xwiki-platform-crypto module by implementing the changes referenced in commit 26728f3 and recompiling the module. No known exploits are currently reported in the wild, but the use of SHA-1 in certificate signatures remains a critical cryptographic weakness that could be leveraged in targeted attacks or man-in-the-middle scenarios if exploited. This vulnerability falls under CWE-327, which concerns the use of broken or risky cryptographic algorithms that compromise security assurances.

For European organizations utilizing the XWiki Platform, this vulnerability poses a risk primarily to the integrity and trustworthiness of internal or external communications secured via certificates generated by the vulnerable Crypto API. If attackers exploit the SHA-1 weakness, they could potentially create forged certificates that appear legitimate, enabling man-in-the-middle attacks, unauthorized access, or data interception. This could lead to exposure of sensitive information, disruption of collaboration workflows, and damage to organizational reputation. Given that XWiki is often used in enterprise and governmental environments for knowledge management and documentation, the impact could extend to critical internal processes and confidential data. The absence of known exploits reduces immediate risk, but the cryptographic weakness remains a latent threat, particularly for organizations with stringent compliance requirements such as GDPR. Additionally, the vulnerability could undermine trust in digital signatures and certificates within affected systems, complicating secure communications and authentication mechanisms.

European organizations should prioritize upgrading their XWiki Platform installations to versions 13.10.6, 14.3.1, or later patched releases to ensure the Crypto API uses SHA-256 with RSA for certificate signatures. If immediate upgrade is not feasible, organizations should apply the local patch to the xwiki-platform-crypto module as specified in commit 26728f3, followed by recompilation and thorough testing in a staging environment before deployment. Administrators should audit all certificates generated by the vulnerable versions and replace any SHA-1 signed certificates with SHA-256 signed equivalents to prevent trust issues. It is also advisable to review and harden certificate validation policies within the organization to detect and reject weak or suspicious certificates. Monitoring network traffic for unusual certificate usage or anomalies can help detect potential exploitation attempts. Finally, organizations should integrate this vulnerability into their risk management and incident response plans, ensuring readiness to respond if exploitation is detected.