CVE-2026-49884 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 an incorrect 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 • 09/08/2026
The vulnerability identified in the rw_mfc_handle_read_op function within rw_mcc.cc represents a critical memory safety flaw characterized by an insufficient boundary validation mechanism during read operations. This specific implementation error allows for an out-of-bounds write, which occurs when the application fails to correctly verify that the destination buffer has sufficient allocated space relative to the size of the data being written or processed. In systems programming contexts involving media framework components such as rw_mfc, memory management is often handled at a low level where manual bounds checking is required rather than relying on automatic safeguards provided by higher-level languages. The absence of this critical validation step means that if an attacker can influence the parameters passed to this function, they can force the application to write data beyond the allocated limits of the target buffer. This type of flaw falls squarely under CWE-787, which classifies out-of-bounds writes as a severe memory corruption vulnerability capable of destabilizing system integrity and security posture.
The operational impact of this vulnerability is significant due to its potential for local privilege escalation without requiring user interaction or additional execution privileges from the attacker. Because no user interaction is needed, an attacker who has already gained access to the affected environment can exploit this flaw autonomously through automated scripts or malicious processes running with lower-level permissions. The ability to write outside of allocated memory boundaries typically allows an attacker to overwrite adjacent memory structures, such as function pointers, return addresses on the stack, or metadata associated with heap allocations. By carefully crafting these overwrites, a local user can manipulate control flow within the privileged process hosting the rw_mfc component, thereby executing arbitrary code in the context of that higher-privileged application. This aligns with ATT&CK technique T1068, which covers exploitation for privilege escalation, specifically highlighting how memory corruption vulnerabilities are leveraged to bypass existing access controls and gain elevated system rights.
From a technical perspective, the root cause lies in the logic governing the read operation where the calculated offset or length is not strictly compared against the maximum allowable size of the buffer before the write instruction is executed. In many multimedia framework implementations, data streams may be processed dynamically based on external inputs such as file headers, network packets, or device signals. If these inputs are malformed or maliciously crafted to specify a larger payload than expected, the unchecked arithmetic results in a pointer that points to memory locations outside the intended buffer region. This leads to undefined behavior, which security researchers and exploit developers frequently target because it provides a reliable mechanism for achieving code execution. The lack of user interaction further exacerbates the risk profile, as traditional social engineering defenses or manual approval workflows offer no protection against this automated exploitation vector.
Mitigation strategies must focus on rigorous input validation and memory safety improvements within the source code responsible for handling these read operations. Developers should implement strict bounds checking that verifies both the start position and the end position of any write operation against the allocated buffer size before proceeding with data transfer. Utilizing safer programming practices or static analysis tools can help identify such discrepancies during the development lifecycle rather than in production environments. Additionally, employing compiler-based security features such as stack protectors, address space layout randomization, and full RELRO can mitigate the likelihood of successful exploitation even if a vulnerability exists by making it more difficult to predict memory layouts and overwrite critical control data. For system administrators, applying vendor-provided patches that correct this logic error is essential to restore the integrity of the media framework components and prevent unauthorized privilege escalation within the local environment.