CVE-2020-24339
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 picoTCP and picoTCP-NG through 1.7.0. The DNS domain name record decompression functionality in pico_dns_decompress_name() in pico_dns_common.c does not validate the compression pointer offset values with respect to the actual data present in a DNS response packet, causing out-of-bounds reads that lead to Denial-of-Service.
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 confidenceThe DNS domain name record decompression function pico_dns_decompress_name() in picoTCP does not validate compression pointer offset values against the actual data present in DNS response packets. This allows out-of-bounds memory reads when processing compressed DNS names, leading to denial of service.
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<= 1.7.0<= 1.7.0CVSS 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 if picoTCP is in useSearch your codebase, firmware, or software bill of materials for references to picoTCP or picotcp. Check dependency lists, embedded firmware images, or third-party library inventories.Affected if picoTCP or picoTCP-ng is found as a dependency or embedded component
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Determine the picoTCP versionInspect the version string or version header file in the picoTCP library. Look for version.h, picotcp_version.h, or similar version metadata within the library distribution.Affected if The version is 1.7.0 or earlier, or the version cannot be determined (indicating an unpatched older release)
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Check if DNS functionality is enabledReview the build configuration, compile-time flags, or feature toggles for your application/firmware. Look for CONFIG_PICO_DNS, PICO_SUPPORT_DNS, or similar DNS-related configuration options.Affected if DNS support is compiled into the firmware or application
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Verify DNS response processing is reachableAnalyze the network code path to confirm that pico_dns_decompress_name() is actually called during DNS response handling. Check if DNS queries are issued and responses are processed.Affected if The device or application performs DNS lookups and processes responses using picoTCP's DNS functions
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Inspect the DNS decompression functionIf access to the source or binary is available, examine the pico_dns_decompress_name() function for bounds checking on compression pointer offsets. Look for validation that offsets do not exceed packet data length.Affected if The function lacks validation that compression pointers remain within packet bounds, or source/binaries cannot be audited and version is unconfirmed
You are affected if your environment uses picoTCP or picoTCP-ng version 1.7.0 or earlier, has DNS support enabled, and processes DNS responses through the vulnerable decompression function.
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 dataAdd validation checks in pico_dns_decompress_name() to verify compression pointer offsets remain within packet bounds before dereferencing, or upgrade to a patched version if available.
- Consultation3.0 h
- Implementation6.0 h
- Testing8.0 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 $5,472.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-24339 — 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-2020-24339 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
- No spam, self-promotion, credentials, or personal data