CVE-2024-8929 is a vulnerability affecting PHP versions 8.1.* before 8.1.31, 8.2.* before 8.2.26, and 8.3.* before 8.3.14, where the PHP MySQL client library improperly handles responses from a hostile MySQL server. Specifically, a malicious MySQL server can manipulate the client into disclosing contents of its heap memory, which includes data from other SQL queries and potentially sensitive information belonging to different users sharing the same database server. This vulnerability is categorized under CWE-200 (Exposure of Sensitive Information) and CWE-125 (Out-of-bounds Read), indicating that the client reads memory beyond intended boundaries. The attack vector requires network-level access to the MySQL server and a low-privileged attacker, but no user interaction is necessary. The vulnerability impacts confidentiality but does not affect integrity or availability. The scope is significant in multi-tenant or shared hosting environments where multiple users’ data reside on the same database server, increasing the risk of cross-user data leakage. The CVSS v3.1 score is 5.8 (medium), reflecting the moderate ease of exploitation due to the need for a hostile MySQL server and some privileges, but high impact on confidentiality. No public exploits have been reported yet, but the vulnerability’s presence in widely deployed PHP versions makes it a notable risk. The PHP Group has published patches in versions 8.1.31, 8.2.26, and 8.3.14 to address this issue, although no direct patch links were provided in the source data. Organizations using vulnerable PHP versions with MySQL backends should prioritize upgrading to mitigate potential data leaks.

For European organizations, this vulnerability poses a significant risk to the confidentiality of sensitive data managed via PHP applications connected to MySQL databases. Industries such as finance, healthcare, e-commerce, and public sector entities that rely heavily on PHP-MySQL stacks could face unauthorized disclosure of personal data, intellectual property, or confidential business information. Multi-tenant hosting providers and cloud services operating in Europe are particularly vulnerable, as the flaw allows a malicious database server to leak data across different users sharing the same infrastructure. This could lead to regulatory non-compliance under GDPR due to unauthorized data exposure, resulting in legal penalties and reputational damage. The medium severity score reflects that while exploitation requires some attacker capabilities (hosting a malicious MySQL server or compromising an existing one), the impact on confidentiality is high. The vulnerability does not affect data integrity or system availability, but the breach of sensitive information can have cascading effects on trust and operational security. European organizations with complex supply chains or third-party hosting arrangements should be vigilant, as the vulnerability could be exploited indirectly via compromised database servers.

1. Upgrade PHP installations to versions 8.1.31, 8.2.26, or 8.3.14 or later, where this vulnerability is patched. 2. Restrict MySQL server access strictly to trusted hosts and networks, minimizing exposure to potentially hostile servers. 3. Implement network segmentation to isolate database servers from untrusted or external networks, reducing the risk of attacker-controlled MySQL servers. 4. Monitor database client-server communications for anomalies that could indicate manipulation attempts or unexpected data leakage. 5. For multi-tenant environments, consider additional isolation mechanisms such as separate database instances or containers per tenant to limit cross-user data exposure. 6. Review and harden database user privileges to the minimum necessary, preventing attackers from easily establishing hostile MySQL servers. 7. Employ runtime application self-protection (RASP) or database activity monitoring tools that can detect unusual memory access patterns or data leaks. 8. Conduct regular security audits and penetration tests focusing on database interactions and PHP-MySQL client behavior. These steps go beyond generic patching by emphasizing network controls, monitoring, and architectural isolation to reduce attack surface and impact.