CVE-2025-43300 is a memory corruption vulnerability in Apple macOS and related Apple operating systems, including iPadOS and newer macOS versions such as Sonoma, Ventura, and Sequoia. The vulnerability arises from an out-of-bounds write condition during the processing of a maliciously crafted image file. Specifically, the issue is due to insufficient bounds checking, which allows an attacker to write data outside the intended memory buffer boundaries. This can lead to memory corruption, potentially enabling arbitrary code execution or system compromise. Apple has acknowledged that this vulnerability has been exploited in highly sophisticated targeted attacks against specific individuals, indicating that threat actors have weaponized this flaw in real-world scenarios. The vulnerability affects multiple Apple OS versions, and patches have been released in macOS Sonoma 14.7.8, Ventura 13.7.8, Sequoia 15.6.1, iOS 18.6.2, and iPadOS 17.7.10 and 18.6.2. The exploit vector involves processing a malicious image file, which could be delivered via email, web downloads, or other file-sharing mechanisms. Given the nature of the vulnerability, exploitation likely requires user interaction to open or preview the malicious image file. No CVSS score has been assigned yet, but the vulnerability is critical due to the potential for remote code execution and the fact it has been exploited in the wild. The lack of a CVSS score and limited public technical details suggest this is a zero-day or recently disclosed vulnerability with active exploitation in targeted attacks.

For European organizations, this vulnerability poses a significant risk, especially to entities using Apple devices extensively, such as government agencies, financial institutions, and enterprises with macOS or iPadOS endpoints. Successful exploitation could lead to unauthorized access, data theft, espionage, or persistent footholds within critical networks. The fact that the vulnerability has been used in highly sophisticated targeted attacks suggests that advanced persistent threat (APT) groups may leverage it for espionage or sabotage. Confidentiality and integrity of sensitive data could be compromised, and availability could be affected if attackers deploy destructive payloads. Organizations relying on Apple hardware for sensitive communications or operations are particularly vulnerable. The user interaction requirement means phishing or social engineering campaigns could be used to deliver the malicious image payload. Given the widespread use of Apple devices in Europe, especially in sectors like finance, technology, and government, the impact could be broad if exploited at scale.

European organizations should prioritize immediate patching of all affected Apple operating systems with the released updates (macOS Sonoma 14.7.8, Ventura 13.7.8, Sequoia 15.6.1, iOS 18.6.2, iPadOS 17.7.10 and 18.6.2). Beyond patching, organizations should implement strict email and file filtering to block or quarantine suspicious image files, especially from untrusted sources. Deploy endpoint detection and response (EDR) solutions capable of monitoring for anomalous memory corruption behaviors or exploitation attempts on Apple devices. User awareness training should be enhanced to educate about the risks of opening unsolicited image files and recognizing phishing attempts. Network segmentation can limit lateral movement if a device is compromised. Additionally, organizations should monitor threat intelligence feeds for indicators of compromise related to this vulnerability and conduct regular audits of Apple device security posture. For high-value targets, consider disabling automatic image previews in email clients or messaging apps to reduce attack surface. Incident response plans should be updated to include this vulnerability and potential exploitation scenarios.