CVE-2025-43240 is a logic vulnerability identified in Apple Safari, specifically affecting the way the browser associates the origin of downloaded files. The issue arises from improper origin association during the download process, which can lead to a download being incorrectly linked to a different origin than its true source. This vulnerability is categorized under CWE-703 (Improper Check or Handling of Exceptional Conditions), indicating that the flaw stems from insufficient validation or logic errors in the code handling download origin attribution. The vulnerability affects Safari versions prior to 18.6 and macOS versions before Sequoia 15.6, where the fix has been implemented. The CVSS v3.1 base score is 6.2, reflecting a medium severity level. The vector string (AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N) indicates that exploitation requires local access (AV:L), has low attack complexity (AC:L), does not require privileges or user interaction, and impacts confidentiality with high impact (C:H), but does not affect integrity or availability. The flaw could allow an attacker with local access to misattribute the origin of a downloaded file, potentially misleading security controls or users about the source of the file. Although no known exploits are currently reported in the wild, the vulnerability's presence in a widely used browser component means it could be leveraged in targeted local attacks or combined with other vulnerabilities to escalate risk. The root cause is a logic error in the origin association mechanism, which Apple addressed by improving the checks that validate download origins in the affected software versions.

For European organizations, this vulnerability poses a moderate confidentiality risk, particularly in environments where local access to user machines is possible, such as shared workstations, corporate offices, or managed service providers. Misassociation of download origins could undermine security policies that rely on origin-based trust decisions, such as sandboxing, content filtering, or download blocking. Attackers with local access could exploit this flaw to disguise the provenance of malicious files, potentially bypassing security controls or deceiving users into trusting harmful content. This could facilitate subsequent malware execution, data exfiltration, or lateral movement within networks. Although the vulnerability does not directly impact integrity or availability, the confidentiality breach could lead to exposure of sensitive information or enable further exploitation. Given the widespread use of Safari on macOS devices in European enterprises, especially in sectors like finance, technology, and government, the risk is non-trivial. However, the requirement for local access limits remote exploitation, reducing the threat surface compared to network-exploitable vulnerabilities.

European organizations should prioritize updating affected systems to macOS Sequoia 15.6 and Safari 18.6 or later, where the vulnerability is patched. Beyond patching, organizations should enforce strict endpoint security policies that limit local access to trusted personnel only, reducing the risk of local exploitation. Implementing application whitelisting and robust download monitoring can help detect and block suspicious files regardless of origin attribution. Security teams should audit and enhance their origin-based security controls to verify their effectiveness against misattribution scenarios. User education on the risks of executing downloaded files from untrusted sources remains critical. Additionally, deploying endpoint detection and response (EDR) solutions that monitor for anomalous file download and execution behaviors can provide early warning of exploitation attempts. For managed environments, restricting the installation of unauthorized software and enforcing least privilege principles will further mitigate risk. Finally, organizations should maintain up-to-date inventories of macOS devices running Safari and ensure timely deployment of security updates.