CVE-2024-31083 is a use-after-free vulnerability identified in the ProcRenderAddGlyphs() function of Xorg servers, specifically affecting version 21.1.12. The vulnerability stems from improper management of glyph memory when AllocateGlyph() is called to store new glyphs sent by clients. Because these glyphs are not reference counted, multiple entries may point to the same glyph object. When ProcRenderAddGlyphs() frees one glyph, other entries still reference the freed memory, leading to a use-after-free condition. This memory corruption can be exploited by an authenticated attacker with low privileges who sends a specially crafted request to the X server, enabling arbitrary code execution. The vulnerability impacts confidentiality, integrity, and availability by allowing code execution at the privilege level of the X server process. The CVSS 3.1 score of 7.8 reflects the high impact and relatively low complexity of exploitation, requiring local access and privileges but no user interaction. No public exploits have been observed yet, but the risk remains significant due to the widespread use of Xorg in Linux graphical environments. The flaw highlights the importance of proper memory management and reference counting in graphical subsystems to prevent use-after-free vulnerabilities.

For European organizations, this vulnerability poses a significant risk, particularly for those relying on Linux-based systems running Xorg version 21.1.12. The ability for an authenticated attacker to execute arbitrary code can lead to full system compromise, data breaches, disruption of services, and potential lateral movement within networks. Critical infrastructure sectors such as finance, government, energy, and telecommunications that use Linux graphical environments may face operational disruptions and data integrity issues. The vulnerability's exploitation could undermine trust in affected systems and lead to regulatory and compliance challenges under GDPR and other data protection laws. Since the vulnerability requires local authentication, insider threats or compromised user accounts increase the risk. Organizations with remote access to vulnerable systems must be vigilant, as attackers could leverage stolen credentials to exploit this flaw.

European organizations should immediately identify and inventory systems running Xorg version 21.1.12 or affected versions. Applying vendor patches or updates as soon as they become available is critical. In the absence of patches, organizations should restrict access to X servers by limiting user privileges and network exposure, enforcing strict access controls, and using multi-factor authentication to reduce the risk of unauthorized access. Monitoring and logging of X server requests can help detect anomalous or suspicious activity indicative of exploitation attempts. Employing application whitelisting and endpoint detection and response (EDR) solutions can provide additional layers of defense. Security teams should conduct regular vulnerability scans and penetration tests to identify and remediate this and related vulnerabilities. Educating users about the risks of credential compromise and enforcing strong password policies will reduce the likelihood of exploitation. Finally, isolating critical systems and implementing network segmentation can limit the impact of a successful attack.