CVE-2026-58839 in Android
Summary
by MITRE • 09/09/2026
In forEachLine of MountRegistry.cpp, there is a possible out of bounds read due to a 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 forEachLine function within MountRegistry.cpp represents a critical memory safety issue characterized by an out-of-bounds read resulting from improper boundary checks during buffer operations. This flaw typically arises when software processes input data without adequately verifying that the length of the incoming string or file content does not exceed the allocated size of the destination buffer. In this specific context, the MountRegistry component is responsible for managing mount points and registry entries within an operating system environment, a process that often involves parsing configuration files or system logs line by line. When the forEachLine function encounters input where the delimiter handling or length calculation fails to account for null terminators or trailing characters correctly, it may attempt to read memory locations beyond the intended buffer boundaries. This behavior is a classic manifestation of CWE-126, which denotes Buffer Over-read, and often overlaps with CWE-787, Out-of-bounds Read, depending on whether the overflow leads to reading sensitive data from adjacent memory or causes a crash due to accessing unmapped pages.
The operational impact of this vulnerability extends beyond simple application instability because it facilitates local privilege escalation without requiring additional execution privileges for the attacker. In many operating system architectures, components like MountRegistry operate with elevated permissions to manage file systems and device mounts securely. If an unprivileged user can trigger this out-of-bounds read through a crafted input that does not require direct interaction or complex exploitation steps, they may be able to leak sensitive kernel memory contents such as stack cookies, pointers to other security structures, or credentials stored in adjacent memory regions. This information leakage is particularly dangerous as it undermines the isolation mechanisms designed to protect privileged processes from untrusted users. The absence of a requirement for user interaction significantly lowers the barrier to entry for exploitation, allowing automated scripts or malicious background services to trigger the flaw repeatedly until sufficient data is exfiltrated to facilitate further attacks.
From an offensive security perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework, specifically those related to Discovery and Defense Evasion. The out-of-bounds read can be leveraged as part of a broader attack chain where leaked memory contents are used to bypass stack-based protections or identify target addresses for subsequent code execution attempts. While the primary description highlights an information disclosure vector via over-read, such flaws often serve as precursors to more severe exploits if combined with other weaknesses like use-after-free conditions or improper type casting in adjacent logic blocks. The fact that no additional privileges are needed implies that any local user account on the system can potentially exploit this flaw, making it a high-risk issue for multi-user environments or systems where privilege separation is critical for security posture.
Mitigation strategies must focus on rigorous input validation and memory safety practices within the source code of MountRegistry.cpp. Developers should implement strict length checks before copying data into buffers, ensuring that the size of the input does not exceed the allocated buffer capacity minus one byte to accommodate null terminators where applicable. Utilizing safe string handling functions or modern language features that enforce bounds checking can prevent these errors from occurring in the first place. Additionally, enabling compiler-level protections such as Stack Canaries, Address Space Layout Randomization (ASLR), and Control Flow Integrity (CFI) can mitigate the impact of exploitation by making it significantly harder for attackers to predict memory layouts or execute arbitrary code even if they successfully read out-of-bounds data. Regular static analysis using tools configured to detect CWE-126 patterns is also recommended to identify similar vulnerabilities across the codebase before deployment.