CVE-2021-27698
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 · uneditedRIOT-OS 2021.01 contains a buffer overflow vulnerability in /sys/net/gnrc/routing/rpl/gnrc_rpl_control_messages.c through the _parse_options() function.
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 · moderate confidenceBuffer overflow vulnerability in the _parse_options() function within RPL (Routing Protocol for Low-Power and Lossy Networks) control message parsing code in RIOT-OS 2021.01. The function fails to properly validate buffer sizes when parsing RPL options, allowing remote attackers to overwrite adjacent memory via specially crafted RPL control messages.
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= 2021.01CVSS 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 checksWork through these to decide whether this CVE applies to you.
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Confirm RIOT-OS is in useIdentify whether your embedded device or project uses RIOT-OS as its operating system. This may be documented in your project files, build system, or device specifications.Affected if The device or project does not run RIOT-OS - this CVE only applies to RIOT-OS installations
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Check RIOT-OS versionDetermine the installed or compiled RIOT-OS version. This is typically found in the build artifacts, firmware metadata, or version tags in your RIOT-OS checkout directory. Compare your version against the affected release: 2021.01.Affected if Your version is exactly 2021.01 - earlier or later versions may have different vulnerability status
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Verify RPL module is enabledInspect your application or board configuration to determine if the RPL (Routing Protocol for Low-Power and Lossy Networks) module is compiled and enabled. Check for RPL-related configuration flags or modules in your build configuration (such as 'USEMODULE=rpl' or similar in your Makefile or Kconfig).Affected if RPL module is not included or enabled in your build - the vulnerability only affects systems actively using RPL for network routing
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Check for RPL network activityMonitor network traffic or inspect logs to confirm the device is actively participating in RPL network operations, as the vulnerability is triggered during RPL control message parsing.Affected if The device processes RPL control messages - the buffer overflow occurs when parsing specially crafted RPL options in incoming messages
You are affected if your device runs RIOT-OS version 2021.01, has the RPL module enabled, and actively processes RPL control messages on the network.
Generated from the published advisory. Verify against your own configuration.
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 dataUpgrade to patched RIOT-OS version; if unavailable, implement network filtering of malformed RPL messages and isolate affected IoT devices via network segmentation.
- Consultation8.0 h
- Implementation16.0 h
- Testing12.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $11,200.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-27698 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2021-27698 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
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