CVE-2025-5745 is a medium-severity vulnerability found in the GNU C Library (glibc) version 2.40 and later, specifically affecting the strncmp function implementation optimized for IBM Power10 processors. The issue arises because the strncmp function writes to vector registers v20 to v31 without preserving their original contents. According to the powerpc64le ABI (Application Binary Interface), these registers are designated as non-volatile, meaning that their contents must be preserved across function calls. The failure to save and restore these registers leads to unintended overwriting of data that the caller function expects to remain intact. This can cause two primary security concerns: first, it may alter the control flow of the calling program, potentially leading to unpredictable behavior or exploitation opportunities; second, it can leak the input strings passed to strncmp into other parts of the program, risking information disclosure. The vulnerability is rooted in improper handling of register preservation (CWE-665: Improper Initialization), and it specifically impacts systems running on the powerpc64le architecture with Power10 processors using glibc 2.40 or newer. The CVSS v3.1 base score is 5.6, indicating a medium severity level, with the vector indicating network attack vector (AV:N), high attack complexity (AC:H), no privileges required (PR:N), no user interaction (UI:N), unchanged scope (S:U), and low impacts on confidentiality, integrity, and availability (C:L/I:L/A:L). There are no known exploits in the wild at the time of publication, and no patches have been linked yet, suggesting that mitigation may require updates from the glibc maintainers or workarounds at the system level.

For European organizations, the impact of CVE-2025-5745 depends largely on their use of Power10-based systems running glibc 2.40 or later. Organizations relying on IBM Power10 servers, which are often used in enterprise environments for high-performance computing, databases, and critical infrastructure, could face risks of data leakage and control flow manipulation. The vulnerability could lead to subtle corruption of application state or exposure of sensitive string data, potentially undermining confidentiality and integrity. While the attack complexity is high, the lack of required privileges and user interaction means that remote exploitation is theoretically possible but challenging. The impact on availability is low, but the risk to data confidentiality and integrity could affect compliance with European data protection regulations such as GDPR if sensitive information is leaked. Additionally, critical sectors such as finance, telecommunications, and government that utilize Power10 architectures may face operational risks or reputational damage if the vulnerability is exploited. The absence of known exploits reduces immediate risk, but the presence of this vulnerability in a core system library means that it could be leveraged as part of a multi-stage attack or combined with other vulnerabilities.

European organizations should prioritize identifying systems running on Power10 processors with glibc version 2.40 or later. Since no official patches are currently linked, organizations should monitor glibc project communications for updates or security advisories providing fixes. In the interim, mitigation can include: 1) Restricting network access to vulnerable systems to trusted sources only, reducing exposure to remote attacks. 2) Employing application-level input validation and memory protection mechanisms to limit the impact of corrupted control flow. 3) Utilizing compiler or runtime options that enforce stricter register preservation or enable additional runtime checks if available. 4) Conducting thorough code audits and testing on affected systems to detect anomalous behavior caused by register corruption. 5) Considering temporary architectural workarounds such as disabling the optimized strncmp implementation for Power10 if feasible, or using alternative string comparison functions. 6) Enhancing monitoring and logging around affected systems to detect potential exploitation attempts early. 7) Planning for rapid deployment of patches once released by glibc maintainers. These steps go beyond generic advice by focusing on architecture-specific mitigations and proactive system hardening tailored to the vulnerability's nature.