CVE-2026-22211 in TinyOS
Summary
by MITRE • 01/14/2026
TinyOS versions up to and including 2.1.2 contain a global buffer overflow vulnerability in the printfUART formatted output implementation used within the ZigBee / IEEE 802.15.4 networking stack. The implementation formats output into a fixed-size global buffer and concatenates strings for %s format specifiers using strcat() without verifying remaining buffer capacity. When printfUART is invoked with a caller-controlled string longer than the available space, the unbounded sprintf/strcat sequence writes past the end of debugbuf, resulting in global memory corruption. This can cause denial of service, unintended behavior, or information disclosure via corrupted adjacent global state or UART output.
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Analysis
by VulDB Data Team • 01/14/2026
The vulnerability identified as CVE-2026-22211 represents a critical buffer overflow flaw within the TinyOS operating system version 2.1.2 and earlier implementations. This issue specifically targets the printfUART function that serves as the formatted output mechanism within the ZigBee/IEEE 802.15.4 networking stack, making it particularly dangerous for embedded IoT devices that rely on these communication protocols. The vulnerability stems from improper bounds checking in the implementation that handles string formatting operations, creating a scenario where attacker-controlled input can trigger memory corruption. The affected system utilizes a fixed-size global buffer named debugbuf for storing formatted output, which becomes compromised when the sprintf and strcat functions are employed without adequate buffer capacity verification.
The technical exploitation of this vulnerability occurs through the concatenation of strings using strcat() function without prior validation of available buffer space. When printfUART processes a format string containing %s specifiers with caller-controlled input that exceeds the remaining capacity in debugbuf, the sequential execution of sprintf followed by strcat operations results in writing beyond the allocated buffer boundaries. This unbounded memory access pattern directly violates fundamental security principles and creates multiple attack vectors. The vulnerability manifests as a global buffer overflow because the debugbuf is a globally accessible memory region, meaning that corruption affects the entire system state rather than just a local function scope. The overflow can overwrite adjacent memory locations including other global variables, function return addresses, or critical system state information that maintains the integrity of the ZigBee networking stack.
The operational impact of this vulnerability extends beyond simple denial of service scenarios to encompass potential information disclosure and system instability. When memory corruption occurs, it can lead to unpredictable behavior where the ZigBee networking stack fails to properly process packets, resulting in communication failures that disrupt the entire wireless mesh network. The corrupted global memory state may inadvertently expose sensitive data from adjacent memory regions, creating information disclosure opportunities that could reveal system configuration details, cryptographic keys, or other confidential information. Additionally, the memory corruption can cause function pointers or return addresses to become corrupted, potentially enabling arbitrary code execution under certain conditions or at least causing the system to crash and restart, leading to persistent denial of service. This vulnerability particularly affects embedded systems deployed in industrial control systems, smart grid infrastructure, and wireless sensor networks where reliability and security are paramount.
Mitigation strategies for CVE-2026-22211 should prioritize immediate system updates to TinyOS versions that address this buffer overflow vulnerability through proper bounds checking implementation. System administrators should implement input validation mechanisms that limit the length of strings passed to printfUART functions, particularly when processing user-provided data. The recommended approach involves replacing the unsafe strcat() usage with safer alternatives such as strncat() or implementing comprehensive buffer capacity checks before string concatenation operations. Organizations should also consider implementing memory protection mechanisms including stack canaries, address space layout randomization, and heap integrity checks to provide additional defense-in-depth layers. From a compliance perspective, this vulnerability aligns with CWE-121 and CWE-122 categories related to buffer overflow conditions, and it maps to ATT&CK techniques involving privilege escalation through memory corruption and denial of service attacks. Regular security assessments should include verification of all printf-style functions within embedded systems to identify similar patterns that may present analogous security risks in other components of the system architecture.