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RiotOperating system · Riot Os

CVE-2026-22213

CRITICAL · 9.8 CVSS v3.1 Published 2026-01-12
Fix available
A fix is available. Upgrade to 2025.10 or later.
See remediation →
100/100
Remediation priority · Urgent
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A stack-based buffer overflow exists in the tapslip6 utility's devopen() function where unbounded strcpy() and strcat() operations concatenate the fixed prefix '/dev/' with a user-supplied device name from the -s command-line option into a fixed-size stack buffer without any bounds checking, allowing an attacker to overflow the buffer with excessive input.

MitigationReplace unsafe strcpy()/strcat() with bounded alternatives (strncpy/strncat) and add input length validation to ensure the device name fits within the destination buffer before concatenation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
RiotOperating system
Affected:< 2025.10= 2026.01

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Verify tapslip6 utility is present
    Locate the tapslip6 binary or source code in the RIOT OS environment (typically found inRIOTBOOT/examples/tapslip6 or similar paths)
    Affected if tapslip6 binary exists in the deployed system
  2. Determine RIOT OS version
    Check the installed RIOT OS version against the affected ranges: versions < 2025.10 or exactly 2026.01 are vulnerable
    Affected if RIOT OS version is < 2025.10 or equals 2026.01
  3. Identify tapslip6 usage with -s option
    Inspect how tapslip6 is invoked in your system; look for command-line execution or configuration that passes the -s option to specify a device name
    Affected if tapslip6 is executed with the -s command-line option providing a device name
  4. Check for long device name input
    Review any scripts, configurations, or automated processes that call tapslip6 to see if they pass unusually long strings to the -s parameter
    Affected if The device name supplied via -s can exceed the stack buffer size (typically 64-128 bytes) before the '/dev/' prefix is added

A system is affected if it runs RIOT OS version < 2025.10 or = 2026.01 AND uses the tapslip6 utility with the -s command-line option to specify a device name, because this triggers the unbounded strcpy/strcat in devopen() that causes the buffer overflow.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2025.10 or later
Fixed in 2025.10
Interim mitigation

Replace unsafe strcpy()/strcat() with bounded alternatives (strncpy/strncat) and add input length validation to ensure the device name fits within the destination buffer before concatenation.

Recommended fix High confidence

RIOT OS 2025.10 or later stable release

  1. 1. Identify the current RIOT OS version in use by checking the version banner or version file in your deployment
  2. 2. Download RIOT OS version 2025.10 or later from the official RIOT OS repository (github.com/RIOT-OS/RIOT)
  3. 3. Rebuild the tapslip6 utility from the updated source code using the standard RIOT build system (make clean && make)
  4. 4. Replace the vulnerable tapslip6 binary in your deployment with the newly compiled version
  5. 5. Verify the fix by testing tapslip6 with the -s option using both normal and excessively long input to confirm no buffer overflow occurs
  6. 6. If using RIOT 2026.01, ensure you migrate to the 2025.10 stable release or a subsequent version that includes the bounds-checked fix
Caveat Minor: If custom patches were applied to tapslip6, verify compatibility with the 2025.10 codebase; the build system and API remain consistent

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Riot Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-22213 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
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