CVE-2020-24335
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 uIP through 1.0, as used in Contiki and Contiki-NG. Domain name parsing lacks bounds checks, allowing an attacker to corrupt memory with crafted DNS packets.
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 confidenceA bounds check vulnerability in DNS domain name parsing in uIP 1.0 (used in Contiki and Contiki-NG) allows memory corruption via specially crafted DNS packets due to missing boundary validation during domain name processing.
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<= 1.0CVSS 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
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 uIP version in useLocate the uIP source code or library binary and check its version header/source files. Common locations include uip.h, uip.c, or the Contiki/Contiki-NG platform configuration files. Look for version macros like UIP_VERSION or UIP_VER.Affected if The installed uIP version is 1.0 or any version <= 1.0
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Verify DNS client functionality is enabledCheck the project or platform configuration files for DNS client settings. In Contiki, examine the project's Makefile and look for NETSTACK_CONF_WITH_DNS or similar DNS-related configuration defines. In Contiki-NG, check the YAML configuration for dns-client module inclusion.Affected if DNS client support is compiled into the firmware (DNS must be enabled for the vulnerability to be exploitable)
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Identify DNS packet processing codeSearch the uIP source code for DNS parsing functions, typically in files named uip-dns.c, dns.c, or similar. Look for functions handling DNS responses and domain name decompression/parsing routines.Affected if The system processes DNS responses from the network, which is required for malicious packets to reach the vulnerable parsing code
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Check for boundary validation in domain name parsingExamine the domain name parsing function in the uIP DNS code. Look for buffer length checks before copying domain name labels. Search for memcpy or strcpy calls that handle domain name data without prior bounds verification.Affected if The DNS parsing code lacks proper bounds checking before copying domain name labels into fixed-size buffers, indicating the vulnerability is present
A system is affected if it runs uIP version 1.0 or earlier with the DNS client enabled and processes incoming DNS responses containing domain names.
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 dataImplement proper input validation and bounds checking in DNS domain name parsing code, validating length fields and buffer boundaries before processing domain names from incoming packets.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA3.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,888.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-24335 — 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-2020-24335 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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