CVE-2024-38055 is a medium-severity vulnerability identified in the Microsoft Windows Codecs Library specifically affecting Windows 10 Version 1809 (build 10.0.17763.0). The root cause is improper input validation (CWE-20), which can lead to an information disclosure vulnerability. This means that when the Windows Codecs Library processes certain crafted image or media files, it may improperly handle input data, allowing an attacker with limited privileges (local access with low privileges) to cause the system to leak sensitive information. The vulnerability does not require user interaction to be exploited, but it does require local privileges and low attack complexity. The CVSS 3.1 base score is 5.5, reflecting a medium severity level, with a high impact on confidentiality but no impact on integrity or availability. The scope remains unchanged, meaning the vulnerability affects only the vulnerable component without extending to other system components. There are no known exploits in the wild at the time of publication, and no official patches have been linked yet. This vulnerability could be leveraged by an attacker who has already gained limited access to the system to escalate their information gathering capabilities, potentially aiding further attacks or lateral movement within a network environment.

For European organizations, this vulnerability poses a moderate risk primarily in environments where Windows 10 Version 1809 is still in use, which may include legacy systems or specialized industrial setups. The information disclosure could expose sensitive data such as system details, user information, or other confidential content processed by the codecs library. This leakage could facilitate targeted attacks, social engineering, or privilege escalation attempts. Organizations in sectors with strict data protection regulations, such as finance, healthcare, and government, could face compliance risks if sensitive data is exposed. Additionally, since the vulnerability requires local access, it could be exploited by insiders or attackers who have already compromised a low-privilege account. The lack of user interaction requirement increases the risk of automated or stealthy exploitation once local access is obtained. However, the medium severity and absence of known exploits suggest that immediate widespread impact is limited, but organizations should not delay remediation to prevent potential future exploitation.

European organizations should prioritize upgrading or patching affected systems as soon as Microsoft releases an official fix. In the interim, practical mitigations include restricting local access to trusted users only, enforcing strict access controls and user privilege management to minimize the number of accounts with local login rights on Windows 10 Version 1809 systems. Employing application whitelisting and endpoint detection and response (EDR) solutions can help detect anomalous behavior indicative of exploitation attempts. Network segmentation should be used to isolate legacy systems running this version to limit lateral movement. Regularly auditing and monitoring logs for unusual access patterns or attempts to process suspicious media files can provide early warning signs. Additionally, organizations should consider upgrading to a more recent and supported Windows version where this vulnerability is not present. User education on the risks of opening untrusted files, even locally, remains important despite no user interaction being required for exploitation.