CVE-2024-39479 is a high-severity vulnerability in the Linux kernel's Intel i915 graphics driver, specifically within the hardware monitoring (hwmon) subsystem. The issue arises due to improper management of device-managed resources during device unbinding. In the affected code paths, both the hwmon device and its dependent driver data (drvdata) are device-managed resources expected to be released in a specific order: hwmon should be released before drvdata. However, in the i915 driver, two separate code paths exist that can release either hwmon or drvdata first, violating this expectation. This leads to a use-after-free (UAF) condition if the hwmon sysfs interface is accessed after drvdata has been freed but before hwmon is released. The root cause is the use of devm (device-managed) resource management which does not guarantee the release order required to prevent this UAF. The fix involves removing devm-based management and explicitly releasing and freeing resources during device unbind to ensure correct ordering. The vulnerability can cause high impact on confidentiality, integrity, and availability as indicated by the CVSS 3.1 score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H). Exploiting this flaw requires local privileges but no user interaction, and could allow an attacker to execute arbitrary code or cause denial of service by exploiting the UAF condition in the kernel graphics driver. No known exploits are currently reported in the wild. The vulnerability affects Linux kernel versions containing the specified commit hashes, which correspond to recent kernel versions incorporating the i915 driver.

For European organizations, this vulnerability poses a significant risk especially for those relying on Linux-based systems with Intel integrated graphics using the i915 driver. This includes enterprise servers, workstations, and embedded devices running Linux kernels with the affected versions. Successful exploitation could lead to privilege escalation, arbitrary code execution in kernel space, or system crashes, impacting confidentiality, integrity, and availability of critical systems. Organizations in sectors such as finance, government, telecommunications, and critical infrastructure that use Linux extensively could face operational disruptions or data breaches. The local privilege requirement means attackers need some form of initial access, but once obtained, the vulnerability could be leveraged to gain full control over affected systems. The lack of user interaction requirement facilitates automated exploitation by malicious insiders or malware. Given the widespread use of Linux in European IT environments, the vulnerability could have broad impact if not mitigated promptly.

1. Apply the official Linux kernel patches that remove devm-based resource management in the i915 driver and explicitly manage resource release order during device unbind. Monitor Linux kernel mailing lists and vendor advisories for updated kernel releases addressing CVE-2024-39479. 2. For organizations unable to immediately patch, consider disabling or restricting access to the hwmon sysfs interface related to the i915 driver to limit exposure. 3. Implement strict access controls and monitoring on systems with Intel integrated graphics to detect suspicious local activity that could indicate exploitation attempts. 4. Employ kernel hardening techniques such as Kernel Address Space Layout Randomization (KASLR), Kernel Page Table Isolation (KPTI), and seccomp filters to reduce exploitation likelihood. 5. Conduct thorough audits of local user privileges and limit unnecessary local access to reduce the attack surface. 6. Maintain up-to-date intrusion detection and endpoint protection solutions capable of identifying exploitation attempts targeting kernel vulnerabilities. 7. Test patches in controlled environments before deployment to ensure stability and compatibility with existing workloads.