CVE-2026-55301 in Android
Summary
by MITRE • 09/15/2026
In Wave6VpuDecFlush of wave6.c, there is a possible out-of-bounds write due to a missing bounds check. This could lead to local escalation of privilege with no additional execution privileges needed. User interaction is not needed for exploitation.
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Analysis
by VulDB Data Team • 09/15/2026
The vulnerability identified in the Wave6 video processing unit driver, specifically within the wave6VpuDecFlush function located in wave6.c, represents a critical memory safety failure characterized by an out-of-bounds write condition. This flaw stems from a fundamental absence of bounds checking when handling input parameters or internal state variables during the decoding flush operation. In embedded systems and kernel-space drivers, such operations are often triggered to reset hardware states or clear buffers after a stream discontinuity or error recovery sequence. The lack of validation allows an attacker to supply crafted inputs that exceed the allocated memory boundaries for buffer descriptors or control structures managed by the driver. This unchecked access results in writing data beyond the intended limits of the kernel heap or specific device-specific memory regions, corrupting adjacent memory structures and potentially overwriting critical metadata such as function pointers, object headers, or security cookies embedded within the kernel space.
From a technical perspective, this vulnerability aligns with CWE-787, which classifies out-of-bounds writes that can lead to arbitrary code execution or privilege escalation. The operational impact is severe because it facilitates local escalation of privilege without requiring additional execution privileges on the target system. This means that any user account, even one with minimal permissions such as a guest or unprivileged service account, can potentially exploit this flaw by triggering the affected function through standard API calls associated with video decoding operations. Since user interaction is not required for exploitation, an attacker does not need to trick a privileged user into performing specific actions; instead, they can automate the trigger via background processes or malicious applications that interact with the multimedia subsystem. This significantly lowers the barrier to entry for attackers and increases the likelihood of successful compromise in multi-user environments or cloud-based services where video processing is offloaded to such hardware accelerators.
The exploitation vector typically involves manipulating the parameters passed to the VPU decoder flush routine, potentially by crafting a malformed media stream or sending specific ioctl commands that force the driver into an error state requiring a flush operation with invalid buffer indices. By carefully controlling the out-of-bounds write, an attacker can achieve arbitrary kernel memory writes, which is a primary step in many privilege escalation chains. This capability allows for the modification of kernel data structures to redirect execution flow or disable security mechanisms such as Kernel Address Space Layout Randomization (KASLR) protections if combined with information disclosure vulnerabilities. The absence of user interaction further exacerbates the risk, as background services that handle video transcoding or streaming could be exploited without any direct engagement from system users, making this a high-risk vulnerability for server-side deployments and IoT devices alike.
Mitigation strategies must focus on both immediate patching and long-term architectural improvements within the driver codebase. The primary remediation is to implement rigorous bounds checking in the wave6VpuDecFlush function before accessing any array elements or buffer descriptors. Developers should validate all input parameters against known maximum limits defined by the hardware specification and ensure that indices are strictly less than the allocated size of relevant arrays. Additionally, incorporating static analysis tools configured to detect out-of-bounds access patterns during the development phase can help prevent similar regressions. From a defense-in-depth perspective, enabling Kernel Self-Protection (KSP) features such as stack protectors and hardened usercopy mechanisms can mitigate the impact by detecting memory corruption attempts at runtime. Furthermore, restricting device node permissions so that only trusted processes can invoke video decoding ioctls reduces the attack surface for unprivileged users.
In terms of industry standard mapping, this vulnerability is closely associated with MITRE ATT&CK technique T1068, which covers Exploitation for Privilege Escalation. Specifically, it falls under sub-techniques involving memory corruption exploits that allow attackers to gain higher-level access on the operating system. The lack of bounds checking also reflects weaknesses in input validation practices often cited in CWE-20, Improper Input Validation. Addressing this issue requires a comprehensive review of all entry points into the Wave6 VPU driver to ensure consistent application of security checks across similar functions that handle buffer management and hardware state transitions. Regular auditing of kernel drivers for memory safety issues is essential given their privileged nature and direct interaction with hardware resources, ensuring that vulnerabilities like this out-of-bounds write do not serve as a foothold for deeper system compromise.