CVE-2026-28639 in Android
Summary
by MITRE • 09/08/2026
In rw_mfc_handle_read_op of rw_mfc.cc, there is a possible out of bounds write due to a logic error in the code. 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 • 09/09/2026
The vulnerability identified within the rw_mfc_handle_read_op function located in the rw_mfc.cc source file represents a critical memory safety issue characterized by an out-of-bounds write condition. This flaw stems from a fundamental logic error in how buffer boundaries are calculated or enforced during read operations involving Media Foundation Codec (MFC) handles. In typical implementations of such handlers, input data is processed and written into allocated buffers based on expected sizes derived from header fields or length parameters provided by the caller. However, due to insufficient validation checks or incorrect arithmetic logic within this specific function, the application fails to properly constrain the write operation relative to the actual size of the destination buffer. Consequently, when a crafted input triggers this code path, data is written beyond the allocated memory region, overwriting adjacent heap metadata or other critical structures in memory. This type of vulnerability falls squarely under CWE-787: Out-of-bounds Write, which describes situations where software writes data to a location outside the intended buffer boundary, potentially leading to arbitrary code execution or denial of service depending on what is overwritten and how it is subsequently accessed by the application logic.
The operational impact of this flaw is severe because it facilitates local privilege escalation without requiring additional privileges for exploitation. Since the vulnerability exists within a component that likely runs with elevated system-level permissions or interacts directly with kernel-mode interfaces, an attacker who can trigger this specific code path can manipulate memory structures to gain control over program execution flow. The absence of user interaction requirements significantly lowers the barrier for exploitation, allowing automated attacks or remote triggers if the vulnerable service is exposed via network protocols that invoke these read operations. This aligns with ATT&CK technique T1068: Exploitation for Privilege Escalation, where adversaries leverage software vulnerabilities to increase their access level on a compromised system. By exploiting this out-of-bounds write, an attacker can potentially overwrite function pointers or return addresses stored in adjacent memory locations, thereby redirecting execution to malicious shellcode injected into the process space. This capability enables the transformation of a low-privileged user account into one with administrative rights, compromising the integrity and confidentiality of the entire system environment.
Mitigation strategies for this vulnerability must address both immediate remediation and long-term architectural improvements. The primary corrective action involves patching the rw_mfc_handle_read_op function to implement rigorous bounds checking before any write operations occur. Developers should validate all length parameters against the actual allocated buffer size, ensuring that no write exceeds the designated memory limits. Additionally, employing static analysis tools during the software development lifecycle can help identify similar logic errors in other parts of the codebase that handle media streams or codec data. From a defensive perspective, implementing Memory Protection Extensions such as Data Execution Prevention (DEP) and Address Space Layout Randomization (ASLR) can mitigate the impact by making it more difficult for attackers to reliably execute injected code, although these measures do not prevent the initial memory corruption. Organizations should also enforce strict input validation policies at all entry points where external data is processed, particularly in components dealing with multimedia frameworks that are historically prone to complex parsing logic errors. Regular security audits and penetration testing focused on buffer overflow scenarios will further ensure that such vulnerabilities are detected and resolved before they can be exploited in production environments.