CVE-2026-49879 in Android
Summary
by MITRE • 09/08/2026
In multiple functions of rw_t3t.cc, there is a possible out of bounds write due to an integer overflow. This could lead to remote code execution 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 NDEF reader-writer implementation within rw_t3t.cc represents a critical security flaw rooted in improper handling of arithmetic operations during data processing. Specifically, an integer overflow occurs when calculating buffer sizes or array indices based on input parameters derived from external sources. This type of error typically arises when signed integers are used for calculations that can exceed the maximum representable value, causing the result to wrap around to a negative number or a significantly smaller positive number than intended. In the context of memory management functions such as memcpy or buffer allocation routines, this miscalculation leads to an out-of-bounds write condition where data is written beyond the allocated limits of the target memory region. The presence of this flaw in multiple functions suggests that the underlying logic for validating input lengths and calculating offsets lacks robust boundary checks, allowing attackers to manipulate these values to trigger the overflow consistently across different code paths within the module.
From a technical perspective, an out-of-bounds write is particularly dangerous because it allows an attacker to overwrite adjacent memory structures on the heap or stack. Depending on the specific layout of the application's memory space at runtime, this corruption can target function pointers, return addresses, virtual table pointers in object-oriented code, or other critical control data. By carefully crafting malicious input that triggers the integer overflow and subsequently writes controlled data into these sensitive areas, an attacker can hijack the execution flow of the program. This mechanism is a classic precursor to arbitrary code execution, where the overwritten memory locations are redirected to point to shellcode injected by the attacker or existing library functions like system calls, effectively granting full control over the affected process.
The operational impact of this vulnerability is severe due to its potential for remote exploitation without user interaction. Since the flaw resides in a component likely responsible for handling Near Field Communication (NFC) data exchange via NDEF messages, an adversary can exploit it by simply being within radio range and transmitting specially crafted NFC tags or commands. The lack of required user interaction means that automated attacks are feasible, where malware or malicious actors can trigger the vulnerability passively as a device scans for nearby tags in normal operation scenarios. Furthermore, the requirement for no additional execution privileges lowers the barrier to entry significantly, allowing unprivileged processes or even remote attackers with network access if the NFC stack is exposed through IPC mechanisms to exploit this flaw and achieve code execution on the target system.
This vulnerability aligns closely with Common Weakness Enumeration (CWE) identifiers such as CWE-190 Integer Overflow or Wraparound and CWE-787 Out-of-bounds Write, which describe the root cause and the resulting memory corruption respectively. In terms of offensive security frameworks like MITRE ATT&CK, this exploit path corresponds to techniques involving Memory Corruption for Defense Evasion and Privilege Escalation, specifically leveraging buffer overflows to gain initial access or escalate privileges within the operating system environment. The ability to execute code remotely via NFC interfaces places it in high-risk categories regarding physical proximity attacks against mobile devices, IoT gadgets, or automotive systems that utilize similar communication stacks.
Mitigation strategies must focus on rigorous input validation and safe arithmetic practices throughout the affected functions. Developers should implement explicit checks to ensure that all calculated sizes and indices remain within valid bounds before any memory allocation or copy operation is attempted. Utilizing unsigned integer types for size calculations can help prevent negative wrap-around issues, although careful attention must still be paid to subtraction operations which might underflow if not handled correctly. Additionally, employing compiler-based protections such as stack canaries, Address Space Layout Randomization (ASLR), and Data Execution Prevention (DEP) can provide layers of defense that make exploitation more difficult by randomizing memory layouts and preventing the execution of injected code in writable memory regions. Regular static analysis using tools designed to detect integer overflows and dynamic fuzzing with malformed NDEF payloads are essential steps to identify and remediate such vulnerabilities before deployment, ensuring the integrity and security of NFC-enabled applications against sophisticated remote attacks.