CVE-2025-5915 is a heap-based buffer overflow vulnerability identified in the libarchive library, a widely used component for handling archive files in various Linux distributions, including Red Hat Enterprise Linux 10. The vulnerability occurs due to a flaw in the handling of filter blocks during decompression or processing of archive data. Specifically, the size of a filter block can exceed the bounds of the Lempel-Ziv-Storer-Schieber (LZSS) sliding window used internally by libarchive. This causes the library to read beyond the allocated heap buffer, resulting in a heap buffer over-read condition. Such out-of-bounds reads can lead to unpredictable application behavior, including crashes that cause denial of service, or the unintended disclosure of sensitive information residing in adjacent memory regions. The CVSS v3.1 score of 6.6 reflects a medium severity rating, with the vector indicating that exploitation requires local access (AV:L), low attack complexity (AC:L), privileges (PR:L), and user interaction (UI:R). The scope remains unchanged (S:U), with a high impact on confidentiality (C:H) and availability (A:H), but no impact on integrity (I:N). No known exploits are currently reported in the wild, but the vulnerability's presence in a core library used by many applications elevates its risk profile. The vulnerability affects Red Hat Enterprise Linux 10, and potentially other distributions using the same libarchive version, though only Red Hat is explicitly mentioned. The absence of patches at the time of reporting necessitates proactive mitigation steps.

For European organizations, the impact of CVE-2025-5915 can be significant, especially for those relying on Red Hat Enterprise Linux 10 in critical environments such as government, finance, telecommunications, and industrial control systems. Successful exploitation could lead to denial of service conditions, disrupting business operations and service availability. More critically, the heap buffer over-read could expose sensitive information from memory, potentially leaking credentials, cryptographic keys, or other confidential data. This risk is heightened in multi-tenant or shared environments where information disclosure could cross security boundaries. Given the requirement for local privileges and user interaction, the threat is more relevant to insider threats or scenarios where attackers have gained limited access and seek privilege escalation or data exfiltration. The medium severity rating suggests that while the vulnerability is not trivially exploitable remotely, its consequences warrant timely remediation to prevent lateral movement and escalation within networks.

Organizations should monitor Red Hat and libarchive project advisories closely for official patches and apply them promptly once released. Until patches are available, restrict local user access to systems running Red Hat Enterprise Linux 10 to trusted personnel only, minimizing the risk of exploitation. Employ strict user privilege management and enforce the principle of least privilege to reduce the likelihood of attackers gaining the necessary local privileges. Implement application whitelisting and endpoint detection to identify anomalous behavior indicative of exploitation attempts. Additionally, consider using memory protection mechanisms such as Address Space Layout Randomization (ASLR) and heap protection features available in modern Linux kernels to mitigate exploitation impact. Regularly audit systems for unauthorized user accounts and suspicious activity. For environments where libarchive is used in automated processing pipelines, validate and sanitize archive inputs to reduce exposure to crafted malicious archives.