CVE-2026-23787 in Exynos
Summary
by MITRE • 09/14/2026
An issue was discovered in DPU in Samsung Mobile Processor Exynos 1280, 2200, 1380, 1480, 2400, 1580, 2500, 1680, and 2600. A Use-After-Free in the Exynos DRM HDR driver (due to improper cleanup upon vmap failure) leads to a kernel crash.
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Analysis
by VulDB Data Team • 09/14/2026
The vulnerability identified within Samsung Mobile Processors belonging to the Exynos series, specifically models including the 1280, 2200, 1380, 1480, 2400, 1580, 2500, 1680, and 2600, represents a critical memory management flaw in the kernel-level Display Processing Unit driver. This issue is classified as a Use-After-Free vulnerability, which falls under the Common Weakness Enumeration category CWE-416. The root cause lies within the Exynos DRM HDR (High Dynamic Range) subsystem, where improper cleanup procedures are executed when virtual mapping operations fail. In Linux kernel development, vmap functions are used to map virtually contiguous memory into a non-contiguous physical address space, often for handling large buffers or complex data structures required by display drivers. When such an allocation fails, the driver must ensure that any previously allocated resources are correctly released and that pointers referencing those resources are nullified to prevent subsequent access attempts.
The technical flaw manifests when the vmap operation encounters a failure condition but does not properly invalidate references to the memory region or release associated structures before proceeding with error handling paths that may still attempt to interact with these invalidated objects. Consequently, if an attacker can trigger this specific code path through crafted display commands or buffer configurations, they induce a state where the kernel retains pointers to freed memory. Subsequent operations within the DRM subsystem will dereference these stale pointers, leading to undefined behavior. In most practical scenarios involving kernel-space Use-After-Free conditions, this results in immediate system instability, typically observed as a kernel panic or an automatic reboot of the device due to protection mechanisms like KASAN (Kernel Address Sanitizer) detecting invalid memory access, or more dangerously, silent corruption that could be exploited for further attacks.
From an operational impact perspective, this vulnerability primarily affects the availability and integrity of mobile devices utilizing these Exynos chips. For end-users, a triggered kernel crash results in device unresponsiveness requiring a hard reset, disrupting normal usage patterns such as video playback or gaming which rely heavily on HDR processing capabilities. However, beyond simple denial-of-service, Use-After-Free vulnerabilities are historically significant because they can often be leveraged to achieve arbitrary code execution with kernel privileges. By carefully controlling the contents of the freed memory region and timing the reallocation of that same memory by other subsystems, an attacker could potentially overwrite function pointers or control flow data structures within the kernel. This aligns with ATT&CK technique T1055, specifically sub-techniques related to process injection or privilege escalation via dynamic library hijacking or direct kernel manipulation, although in mobile environments, it may also facilitate escape from sandboxed applications to gain root-level access on the device.
Mitigation strategies for this vulnerability require both immediate patching and long-term architectural improvements within the driver codebase. The primary remediation involves updating the Exynos DRM HDR driver to ensure that all error handling paths correctly release allocated resources and nullify pointers immediately upon detecting a vmap failure. Developers must implement strict checks after every memory allocation call, ensuring that if an allocation fails, no subsequent code path attempts to access the failed buffer or associated metadata. Additionally, employing static analysis tools during development can help identify similar patterns of improper cleanup in other parts of the display stack. For device manufacturers and users, applying the latest security patches provided by Samsung is essential to close this gap. Furthermore, enabling kernel hardening features such as KASAN on debug builds or ensuring that production kernels have robust memory protection mechanisms active can mitigate the exploitability of similar flaws even if they are not immediately patched in legacy devices.