Exynos MFC Driver CVE-2026-23789

Exploitation requires local code execution on an affected device (AV:L) with at least low-level user privileges (PR:L) - typical of any installed Android application with access to the MediaCodec or V4L2 video encoding API. The device must be powered by one of the listed Exynos SoCs (850, 1080, 2100, 1280, 2200, 1330, 1380, 1480, 2400, 1580, 2500, 2600, 1680, W920, W930, or W1000). High attack complexity (AC:H) is explicitly indicated by the CVSS vector, meaning the attacker must reliably trigger the specific error handling code path in the MFC encoder that causes the double-free, likely requiring precise memory layout control or injected error conditions. Remote exploitation is not applicable (AV:L). No user interaction beyond the attacker's own process execution is required (UI:N). The MFC encoder being accessible to regular Android apps via MediaCodec lowers the practical privilege bar, but AC:H is the key limiting factor for mass exploitation.

The CVSS 7.8 score with vector AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H accurately captures the local privilege escalation character of this flaw. Real-world risk is moderated significantly by AC:H - the attacker must reliably trigger a specific error handling path in the MFC encoder under timing or memory-state conditions that are inherently difficult to control. There is no CISA KEV listing, no EPSS data in the provided input, and no public POC identified, suggesting this is not under active mass exploitation. However, the extremely broad chip coverage (17 Exynos variants spanning Samsung's current mobile and wearable lineup) gives this vulnerability a very large potential attack surface if a reliable exploit materializes. Scope change (S:C) with full C:H/I:H/A:H signals full kernel compromise is achievable once the AC:H threshold is crossed. The input tags 'RCE' and 'Buffer Overflow' are both mislabeled: CVSS AV:L confirms this is a local attack (not remote), and CWE-415 is a double-free (not a buffer overflow).

An unprivileged local application on an affected Samsung Exynos device submits a video encoding job that deliberately triggers an error condition in the MFC encoder driver, causing the kernel driver's error handling path to free a dma_buf reference that was already released. With heap grooming to control kernel allocator state at the time of the double-free (high complexity), the attacker manufactures a dangling pointer, achieves arbitrary kernel memory writes, and escalates to kernel-mode code execution, fully escaping the Android application sandbox.