CVE-2026-48178 in Exynos
Summary
by MITRE • 11/05/2026
Out of bound access in PPC due to race condition in global variable access
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Analysis
by VulDB Data Team • 11/05/2026
The vulnerability described involves an out-of-bounds memory access within the PowerPC architecture implementation, specifically triggered by a race condition during the concurrent modification or reading of a shared global variable. This type of flaw is characteristic of concurrency bugs where multiple threads or execution contexts attempt to access and modify the same data structure without adequate synchronization mechanisms such as mutexes, semaphores, or atomic operations. In the context of PowerPC systems, which are often used in embedded devices, network infrastructure, and legacy enterprise hardware, this race condition can lead to unpredictable behavior depending on the timing of thread execution relative to memory allocation boundaries.
From a technical perspective, the root cause lies in the lack of proper locking or atomicity guarantees around the global variable that serves as an index, counter, or pointer for array access. When two threads execute simultaneously, one may read the current value of the variable while another modifies it between the read and subsequent use. This creates a window where the calculated memory address exceeds the allocated buffer size. On PowerPC architectures, which utilize specific load-store unit behaviors and cache coherency protocols, this misalignment can result in accessing invalid physical or virtual addresses. The processor may attempt to fetch data from an unmapped page or corrupt adjacent memory regions, leading to a segmentation fault, kernel panic, or silent data corruption depending on the operating system's handling of such exceptions.
The operational impact of this vulnerability is severe and multifaceted. In a local context, it allows for privilege escalation if the vulnerable code runs with elevated privileges, enabling an attacker to crash the system (Denial of Service) or potentially execute arbitrary code by manipulating memory contents through heap overflow techniques facilitated by the out-of-bounds write. If exploited remotely, such as in network-facing services that utilize PowerPC-based hardware, it could lead to remote code execution without authentication. The instability introduced by race conditions makes exploitation non-deterministic and challenging, but once achieved, the compromise of system integrity is significant. Attackers might leverage this flaw to bypass security controls or extract sensitive information stored in adjacent memory locations, compromising confidentiality alongside availability and integrity.
This vulnerability aligns with Common Weakness Enumeration (CWE) identifiers such as CWE-362: Concurrent Execution using Shared Resource with Improper Synchronization for Race Condition Vulnerability and CWE-787: Out-of-bounds Write or Read. The lack of synchronization is the primary weakness, while the out-of-bounds access is the direct consequence that leads to exploitation. In terms of MITRE ATT&CK framework mapping, this flaw can be associated with techniques involving memory corruption for privilege escalation (T1068) and potentially execution through exploit redirection if the attacker controls the overwritten data. The race condition aspect also relates to timing-based attacks where precise control over thread scheduling is used to widen the exploitation window.
Mitigation strategies must address both the synchronization issue and the bounds checking mechanisms. Developers should implement robust locking primitives around all accesses to the shared global variable, ensuring that read-modify-write operations are atomic. Using hardware-supported atomic instructions available on modern PowerPC cores can further reduce race windows. Additionally, implementing strict boundary checks before any array or buffer access is critical; these checks must be performed under lock protection to prevent TOCTOU (Time-of-Check to Time-of-Use) vulnerabilities. Code reviews should focus heavily on multi-threaded sections involving shared state variables. For deployed systems, applying vendor-provided patches that update the affected firmware or kernel modules is essential. Security monitoring tools can help detect anomalous behavior resulting from memory corruption attempts, although prevention at the code level remains the most effective defense against this class of vulnerability.