CVE-2020-25112
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 · uneditedAn issue was discovered in the IPv6 stack in Contiki through 3.0. There are inconsistent checks for IPv6 header extension lengths. This leads to Denial-of-Service and potential Remote Code Execution via a crafted ICMPv6 echo packet.
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 confidenceContiki OS through version 3.0 contains improper validation of IPv6 header extension lengths in its IPv6 stack. When processing crafted ICMPv6 echo packets with malformed extension headers, the inconsistent length checks can be exploited, leading to denial of service and potentially remote code execution.
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<= 3.0CVSS 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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Identify Contiki OS versionCheck the Contiki version string in the build configuration, firmware metadata, or system information file (typically found in contiki-conf.h, Makefile, or the firmware image header)Affected if The version is 3.0 or any version below 3.0 (the vulnerability affects all versions up to and including 3.0)
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Verify IPv6 stack is enabledInspect the Contiki configuration file (contiki-conf.h or project-conf.h) for the macro UIP_CONF_IPV6 - confirm it is set to 1 or non-zeroAffected if IPv6 is enabled (UIP_CONF_IPV6 is defined and non-zero) because the vulnerability resides in the IPv6 extension header processing code
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Confirm ICMPv6 echo request handling is activeCheck if the ICMPv6 echo responder is compiled in - look for the uip_icmp6_echo_reply_callback or similar ICMPv6 echo handler code in the Contiki source or configurationAffected if ICMPv6 echo handling is enabled, as the attack vector involves crafted ICMPv6 echo packets with malformed extension headers
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Review IPv6 extension header processing codeExamine the Contiki source files handling IPv6 extension headers (typically in core/net/ipv6/ directory, specifically files dealing with extension header parsing) for length validation logicAffected if The code contains inconsistent or missing validation of extension header length fields, allowing malformed headers to pass unchecked
You are affected if you are running Contiki OS version 3.0 or lower with IPv6 and ICMPv6 echo functionality enabled, and the system processes external ICMPv6 packets.
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 data- Consultation4.0 h
- Implementation8.0 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 $7,616.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-25112 — 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-2020-25112 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
- No weaponised exploit code, or anything meant to cause harm
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