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RiotOperating system · Riot Os

CVE-2026-22214

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
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 ethos utility due to missing bounds checking when processing incoming serial frame data. The vulnerability occurs in the _handle_char() function, where incoming frame bytes are appended to a fixed-size stack buffer without verifying that the current write index remains within bounds. An attacker capable of sending crafted serial or TCP-framed input can cause the current write index to exceed the buffer size, resulting in a write past the end of the stack buffer. This condition leads to memory corruption and application crash.

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

RIOT OS versions up to 2026.01-devel-317 contain a stack-based buffer overflow in the ethos utility's _handle_char() function, where incoming serial frame bytes are written to a fixed-size stack buffer without bounds checking, allowing the write index to exceed buffer bounds and corrupt stack memory.

MitigationAdd explicit bounds checking in _handle_char() to validate the write index against buffer size before each byte write; consider implementing dynamic buffer allocation or using safe memory functions to prevent overflow.

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. Identify RIOT OS installation
    Check the firmware, OS version string, or boot logs for 'RIOT' or 'RIOT-OS' identifiers. On embedded systems, inspect the firmware image or check /proc/version if available.
    Affected if RIOT OS is confirmed to be running on the device
  2. Determine RIOT OS version
    Locate the version file (VERSION file in RIOT source), check the firmware build metadata, or query the system for its RIOT version identifier (riot-version or similar). Compare against the affected ranges: versions < 2025.10 or exactly 2026.01.
    Affected if The installed version is less than 2025.10 or equals 2026.01
  3. Verify ethos utility is in use
    Inspect the build configuration (BOARD, USEMODULE) or the compiled firmware to determine if the 'ethos' networking module is included. Check application Makefiles for 'USEMODULE += ethos' or equivalent.
    Affected if The ethos module is compiled into the firmware
  4. Check network/serial exposure of ethos
    Examine the system configuration, network settings, or device documentation to determine if ethos is configured to accept external serial or TCP-framed input from untrusted sources.
    Affected if Ethos is listening on accessible serial ports or TCP network interfaces that accept external frames
  5. Inspect _handle_char implementation
    If source code access is available, locate the ethos frame handler source file and search for the _handle_char function. Verify whether bounds checking exists on the buffer write index.
    Affected if Source code shows no bounds check on the write index before buffer write operations in _handle_char

A user is affected if their device runs RIOT OS version < 2025.10 or = 2026.01 with the ethos utility enabled and exposed to external serial or TCP-framed input sources.

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.

From vendor data
Upgrade available Upgrade to 2025.10 or later
Fixed in 2025.10
Interim mitigation

Add explicit bounds checking in _handle_char() to validate the write index against buffer size before each byte write; consider implementing dynamic buffer allocation or using safe memory functions to prevent overflow.

Fix this in Riot Scoped from the published advisory
  • Consultation4.0 h
  • Implementation6.0 h
  • Testing6.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,500
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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-2026-22214 in production — separate from our analysis above.

No notes yet

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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
  • No spam, self-promotion, credentials, or personal data