CVE-2025-5918 is a vulnerability identified in the libarchive library, specifically impacting the bsdtar utility used for handling archive files. The flaw is an out-of-bounds read that occurs when file streams are piped into bsdtar. This means that under certain conditions, bsdtar may read memory beyond the intended buffer boundaries. Such out-of-bounds reads can cause unpredictable program behavior, including memory corruption or application crashes, potentially leading to denial-of-service (DoS) conditions. The vulnerability affects Red Hat Enterprise Linux 10, which bundles libarchive and bsdtar as part of its system utilities. The CVSS v3.1 base score is 3.9, indicating a low severity level. The vector string (AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:N/A:L) shows that the attack requires local access (AV:L), low complexity (AC:L), low privileges (PR:L), and user interaction (UI:R). The impact is limited to confidentiality (C:L) and availability (A:L), with no impact on integrity. No known exploits are reported in the wild at this time. The vulnerability arises from improper bounds checking when processing piped file streams, which can be triggered by a local user with some privileges who can supply crafted input to bsdtar. The flaw does not allow remote exploitation or privilege escalation but may be leveraged to cause application crashes or leak small amounts of memory data. Since bsdtar is commonly used for archive extraction and manipulation, this vulnerability could be triggered during routine system operations or by malicious users with local access. However, the requirement for user interaction and local privileges limits the attack surface significantly.

For European organizations, the primary impact of CVE-2025-5918 is the potential for denial-of-service conditions on systems running Red Hat Enterprise Linux 10, particularly those that use bsdtar for automated or manual archive processing. While the confidentiality impact is low, the out-of-bounds read could lead to application crashes or memory corruption, disrupting services that rely on archive extraction. This may affect development environments, build servers, or any system that processes archives via bsdtar. Since exploitation requires local access and user interaction, the risk is more pronounced in environments with multiple users or where untrusted users have shell access. The vulnerability does not enable remote code execution or privilege escalation, so the risk to critical infrastructure or sensitive data leakage is limited. However, denial-of-service attacks could impact availability of services or delay operations, which is a concern for organizations with high availability requirements. European organizations using Red Hat Enterprise Linux 10 in production or development should assess their exposure, especially if they allow local users to run bsdtar or process untrusted archives. The low CVSS score reflects the limited scope and complexity of exploitation, but the vulnerability should be addressed to maintain system stability and security hygiene.

To mitigate CVE-2025-5918, European organizations should apply patches or updates provided by Red Hat as soon as they become available. In the absence of patches, organizations can limit exposure by restricting local user access to systems running Red Hat Enterprise Linux 10, especially limiting who can execute bsdtar or handle archive files. Implement strict user permissions and audit usage of bsdtar to detect unusual or unauthorized archive processing. Consider sandboxing or containerizing processes that handle untrusted archives to contain potential crashes or memory corruption effects. Additionally, educate users about the risks of processing untrusted archive files and enforce policies to avoid running bsdtar on unverified inputs. Monitoring system logs for crashes or abnormal bsdtar behavior can help detect exploitation attempts. For automated systems, validate and sanitize archive inputs before processing to reduce the risk of triggering the vulnerability. Finally, maintain up-to-date backups and ensure recovery procedures are in place to minimize downtime in case of denial-of-service incidents.