CVE-2025-5918 is a security vulnerability identified in the libarchive library, which is widely used for handling archive files in Unix-like operating systems. The vulnerability manifests as an out-of-bounds read error when file streams are piped into the bsdtar utility, a common archiving tool that leverages libarchive. This flaw allows the program to read memory beyond the allocated buffer boundaries, which can result in unpredictable program behavior, including memory corruption or a denial-of-service (DoS) condition. The vulnerability requires local access with low privileges and user interaction to trigger, as indicated by the CVSS vector (AV:L/AC:L/PR:L/UI:R). The impact on confidentiality is limited (C:L), with no integrity impact (I:N), and a low availability impact (A:L). The vulnerability affects Red Hat Enterprise Linux 10, a widely used enterprise-grade Linux distribution, which integrates libarchive and bsdtar for system and application-level archive management. Although no known exploits are currently reported in the wild, the flaw could be leveraged by an attacker with local access to disrupt services or cause application crashes. The vulnerability was published on June 9, 2025, and currently lacks publicly available patches, emphasizing the need for vigilance and proactive mitigation by affected users.

For European organizations, the primary impact of CVE-2025-5918 lies in potential service disruption due to denial-of-service conditions caused by memory corruption or crashes in bsdtar or applications relying on libarchive. While the confidentiality impact is low, the availability of critical systems that use these tools for backup, archiving, or deployment processes could be affected, leading to operational downtime. Organizations with automated pipelines or scripts that process archive files using bsdtar are particularly at risk if untrusted or malformed input is introduced. Given that exploitation requires local access and user interaction, the threat is more relevant in environments where multiple users have shell access or where untrusted users can execute commands. This vulnerability could also be leveraged as part of a multi-stage attack to escalate privileges or disrupt system operations. European sectors with stringent uptime requirements, such as finance, healthcare, and critical infrastructure, may experience operational and reputational impacts if this vulnerability is exploited.

To mitigate CVE-2025-5918, organizations should prioritize updating libarchive and bsdtar to patched versions as soon as they become available from Red Hat or trusted repositories. Until patches are released, restrict local user access to bsdtar and related utilities, especially for untrusted or low-privilege users. Implement strict input validation and sanitization for any archive files processed by automated systems to prevent malformed data from triggering the vulnerability. Employ application whitelisting and monitoring to detect unusual crashes or memory errors associated with bsdtar usage. Additionally, consider isolating archive processing tasks within sandboxed or containerized environments to limit the impact of potential exploitation. Regularly audit user privileges and access controls to minimize the risk of local exploitation. Finally, maintain up-to-date backups and incident response plans to quickly recover from any denial-of-service incidents caused by this vulnerability.