CVE-2026-55294 in Android
Summary
by MITRE • 09/09/2026
In ihevcd_get_tu_data_size of ihevcd_utils.c, there is a possible out of bounds write due to a heap buffer overflow. 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 in the function ihevcd_get_tu_data_size within the file ihevcd_utils.c represents a critical security flaw characterized by an out-of-bounds write resulting from a heap buffer overflow. This specific defect occurs during the processing of High Efficiency Video Coding (HEVC) data, where the software fails to adequately validate input parameters or calculate memory allocation sizes prior to writing data into a pre-allocated heap buffer. The root cause lies in insufficient boundary checks that allow an attacker to supply crafted video streams with malformed headers or payload structures. When the decoder processes these malicious inputs, it miscalculates the required size for temporary units (TUs), leading to write operations that exceed the allocated memory boundaries. This type of error is a classic example of improper input validation where the application trusts external data without verifying its integrity against expected constraints.
From a technical perspective, this heap buffer overflow allows an attacker to overwrite adjacent memory structures on the heap. In modern operating systems, the heap contains various metadata and control structures that are critical for program execution flow. By carefully crafting the overflow payload, an adversary can corrupt these structures, such as function pointers or object headers, which can subsequently be leveraged to redirect code execution. The vulnerability is particularly severe because it resides in a media decoding component, which is often invoked automatically by web browsers, video players, and operating system services when processing embedded multimedia content. This characteristic significantly lowers the barrier for exploitation, as it does not require complex user interaction beyond viewing or loading a malicious file or webpage containing the crafted HEVC stream.
The operational impact of this vulnerability is profound, primarily due to its potential for local privilege escalation. Although the initial execution context may be limited to that of an unprivileged user running a media application, successful exploitation can lead to arbitrary code execution with elevated privileges. This means that if an attacker can trick a privileged process or leverage a setuid binary into processing malicious video data, they could gain full control over the system. The absence of additional execution privileges needed for exploitation further exacerbates the risk, as it implies that standard user-level applications are sufficient vectors for attack. Furthermore, since user interaction is not strictly required beyond triggering the media playback mechanism, automated attacks via drive-by downloads or malicious email attachments become highly feasible.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-120, which describes buffer copy without checking size limits, specifically manifesting as a heap-based overflow under CWE-787. In the context of the MITRE ATT&CK framework, this flaw facilitates techniques associated with Initial Access and Privilege Escalation. Attackers would likely utilize crafted HEVC files to achieve initial code execution (T1203 or T1195) followed by exploitation for privilege escalation (T1068). The lack of user interaction requirement places it in a high-risk category where automated exploit kits can effectively target vulnerable systems without social engineering components.
Mitigation strategies must focus on both immediate patching and long-term defensive coding practices. Developers should immediately apply vendor-provided patches that address the boundary checks within ihevcd_get_tu_data_size to ensure that memory allocations are strictly bounded by validated input sizes. For organizations unable to patch immediately, network-level filtering can be employed to block or inspect HEVC traffic for anomalies in header structures. Additionally, enabling heap hardening features such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) on affected systems can mitigate the likelihood of successful code execution by making it more difficult for attackers to predict memory layouts and execute injected shellcode. Long-term remediation involves integrating static analysis tools into the development pipeline specifically tuned to detect heap buffer overflows in C/C++ media processing libraries, ensuring that future iterations include rigorous input validation and bounds checking before any memory write operations occur.