CVE-2020-13601
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 · uneditedPossible read out of bounds in dns read. Zephyr versions >= 1.14.2, >= 2.3.0 contain Out-of-bounds Read (CWE-125). For more information, see https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-mm57-9hqw-qh44
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 confidenceOut-of-bounds read vulnerability (CWE-125) in Zephyr RTOS DNS parsing code. The DNS read function allows reading beyond allocated buffer boundaries, potentially exposing sensitive memory contents. This occurs in versions >= 1.14.2 and >= 2.3.0.
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<= 1.14.2>= 2.0.0, <= 2.3.0CVSS 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 Zephyr versionCheck the Zephyr kernel version header (typically in zephyr/include/generated/version.h) or examine the build output for the Zephyr version string (e.g., 'Zephyr version X.X.X')Affected if The version is <= 1.14.2 or >= 2.0.0 and <= 2.3.0
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Confirm DNS client is enabledInspect the build configuration (Kconfig or .config file) for CONFIG_DNS_RESOLVER=y or CONFIG_DNS_CLIENT=y settingAffected if DNS client support is compiled into the firmware (the vulnerability only applies when DNS functionality is present)
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Check for network stack usageLook for CONFIG_NETWORKING=y and CONFIG_UDP=y in the build configuration, as DNS over UDP requires the network stackAffected if The network stack with UDP support is enabled (DNS relies on UDP for query/response)
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Verify DNS response handling is usedReview the application code or configuration to confirm the device performs DNS resolution (e.g., calls to getaddrinfo(), dns_get_addr_info(), or equivalent DNS APIs)Affected if The device actively makes DNS queries at runtime (the out-of-bounds read occurs during DNS response parsing)
The environment is affected if the Zephyr version falls within the vulnerable range (1.14.2 or earlier, or 2.0.0 to 2.3.0) AND DNS client functionality is enabled and used in the firmware build.
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.
dbcve · scopedUpgrade Zephyr to a version that includes the security patch from the GHSA-mm57-9hqw-qh44 advisory. If upgrade is not immediately feasible, implement input validation on DNS response sizes before buffer reads.
Zephyr >= 2.4.0 (or latest stable release)
- 1. Identify all Zephyr-based products using affected versions (<=1.14.2 or 2.0.0-2.3.0)
- 2. Check Zephyr release notes for security fixes in versions beyond 2.3.0
- 3. Upgrade Zephyr to version 2.4.0 or later (latest stable release recommended)
- 4. Rebuild and redeploy firmware with the updated Zephyr version
- 5. Verify the DNS functionality works correctly after upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-13601 — 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-2020-13601 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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