RIOT OS tapslip6 Utility Stack-based Buffer Overflow Vulnerability (CVE-2026-22213) Security Advisory
Executive & SecOps Summary
SECOPS ASSESSMENTRIOT OS versions up to and including 2026.01-devel-317 containing the tapslip6 utility
Attackers can trigger a stack buffer overflow via crafted command-line arguments, leading to process crashes and potential arbitrary code execution
Apply the latest source patches, replace unsafe string functions with snprintf, and restrict execution permissions on the tapslip6 binary
Affected Products & Version Scope
Remediation & Live Workaround Commands
PATCH & WORKAROUND1. Official Patch & Version Upgrade Commands
Update your RIOT OS repository to the latest master branch or manually patch the tapslip6.c source file to replace unsafe string operations with bounded functions like snprintf. Rebuild the utility using the commands below:
# Navigate to RIOT repository and pull the latest updates
cd /path/to/RIOT
git fetch origin
git checkout master
git pull
# Rebuild the tapslip6 utility
cd dist/tools/tapslip6
make clean && make2. Temporary Workaround & Hardening Configuration
If patching is not immediately feasible, mitigate the risk by removing the SUID bit from the binary and restricting execution permissions to authorized users only.
# Remove SUID permission and restrict execution access
sudo chmod u-s /usr/local/bin/tapslip6
sudo chmod 750 /usr/local/bin/tapslip63. Log Audit & IoC Verification Commands
Use the following commands to audit the source code for vulnerable patterns and inspect system logs for anomalous execution attempts.
# 1. Scan the source code for unsafe strcpy/strcat usage in tapslip6
grep -rn 'strcpy.*dev' /path/to/RIOT/dist/tools/tapslip6/ || echo '[INFO] No vulnerable strcpy pattern found.'
# 2. Audit system logs for execution of tapslip6 with excessively long arguments
ausearch -p $(pgrep tapslip6) --raw 2>/dev/null | grep -E '\-s [A-Za-z0-9_/]{50,}' || echo '[INFO] No anomalous long arguments detected.'Block Kernel Privilege Escalation & Ransomware Payloads Before You Can Reboot
Protect unpatched Windows, Linux, and macOS workloads against in-memory exploitation and lateral movement with autonomous EDR.
Technical Root Cause & Exploitation Mechanics
1. Vulnerability Overview & Root Cause
This vulnerability (CVE-2026-22213) is a stack-based buffer overflow (CWE-121) in the tapslip6 utility of RIOT OS, an operating system designed for IoT devices. The root cause lies in the devopen() function, which performs unsafe string concatenation when constructing a device path. The utility utilizes strcpy() and strcat() to concatenate the fixed prefix '/dev/' with a user-supplied device name provided via the -s command-line option without any bounds checking.
2. Exploitation Mechanics & Attack Scenario
An attacker can exploit this vulnerability by executing the tapslip6 utility and passing an excessively long device name as an argument to the -s option. Because devopen() copies and concatenates this input into a fixed-size stack buffer without validating its length, the input overflows the buffer boundaries. This corrupts adjacent stack memory, including the saved frame pointer and return address, allowing the attacker to hijack the control flow, crash the process, or execute arbitrary code.
3. Infrastructure & Business Impact
The tapslip6 utility is critical for bridging virtual network interfaces (TAP) with serial lines in RIOT OS environments. If this utility runs with elevated privileges (such as root or via sudo), a local or restricted attacker could leverage this vulnerability to achieve Local Privilege Escalation (LPE). This compromises the integrity of the IoT gateway/development host and disrupts network availability.
Official Vendor Advisories & References
RIOT OS versions up to and including 2026.01-devel-317 contain a stack-based buffer overflow vulnerability in the tapslip6 utility. The vulnerability is caused by unsafe string concatenation in the devopen() function, which constructs a device path using unbounded user-controlled input. The utility uses strcpy() and strcat() to concatenate the fixed prefix '/dev/' with a user-supplied device name provided via the -s command-line option without bounds checking. This allows an attacker to supply an excessively long device name and overflow a fixed-size stack buffer, leading to process crashes and memory corruption.
Frequently Asked SecOps Questions (CVE-2026-22213)
FAQQ1. How critical is CVE-2026-22213 and is it actively exploited in the wild?
CVE-2026-22213 is rated CVSS 9.8 (CRITICAL) with a 30-day EPSS exploitation probability of 0.4%. Organizations running affected versions should prioritize patching based on network exposure.
Q2. Which vendors and products are affected by CVE-2026-22213?
Primary impacted vendors include riot-os across riot os. Scope summary: RIOT OS versions up to and including 2026.01-devel-317 (specifically environments utilizing the tapslip6 tool)
Q3. What temporary mitigations or workarounds exist for CVE-2026-22213 before patching?
[Mitigation] Apply the latest source patches, replace unsafe string functions with snprintf, and restrict execution permissions on the tapslip6 binary Follow the CLI remediation commands and interactive SecOps checklist on this page to restrict exposure prior to your maintenance window.
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