CVE-2020-10030
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 has been found in PowerDNS Recursor 4.1.0 up to and including 4.3.0. It allows an attacker (with enough privileges to change the system's hostname) to cause disclosure of uninitialized memory content via a stack-based out-of-bounds read. It only occurs on systems where gethostname() does not have '\0' termination of the returned string if the hostname is larger than the supplied buffer. (Linux systems are not affected because the buffer is always large enough. OpenBSD systems are not affected because the returned hostname always has '\0' termination.) Under some conditions, this issue can lead to the writing of one '\0' byte out-of-bounds on the stack, causing a denial of service or possibly arbitrary code execution.
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 PowerDNS Recursor versions 4.1.0 through 4.3.0 contain a stack-based out-of-bounds read vulnerability in the handling of gethostname() return values. When the system hostname exceeds the supplied buffer size, the returned string may not be null-terminated on certain platforms (excluding Linux and OpenBSD), leading to disclosure of uninitialized stack memory. Under certain conditions, this can also result in writing a null byte out-of-bounds, potentially causing denial of service or arbitrary 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>= 4.1.0, <= 4.3.0CVSS 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
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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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Check if PowerDNS Recursor is installedRun 'pdns_recursor --version' or 'rec_control version' to confirm the product is presentAffected if No output or command not found indicates the product is not installed
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Identify the installed versionRun 'pdns_recursor --version' and parse the version number from the outputAffected if Version is 4.1.0, 4.1.1, 4.1.2, 4.1.3, 4.1.4, 4.1.5, 4.1.6, 4.1.7, 4.1.8, 4.1.9, 4.1.10, 4.1.11, 4.2.0, 4.2.1, 4.2.2, 4.3.0 (any version >= 4.1.0 and <= 4.3.0)
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Check the operating system platformRun 'uname -s' or check /etc/os-release to identify the OSAffected if Platform is NOT Linux or NOT OpenBSD (the vulnerability specifically does NOT affect Linux and OpenBSD)
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Check the system hostname lengthRun 'hostname' to view the current hostname, then check its character countAffected if Hostname length exceeds the buffer size used internally by gethostname() calls (typically 256 bytes), which is unlikely but the condition exists when hostname is very long
The environment is affected if PowerDNS Recursor version 4.1.0 through 4.3.0 is installed and the platform is not Linux or OpenBSD.
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 PowerDNS Recursor to version 4.3.1 or later to patch this vulnerability. Organizations unable to upgrade immediately should monitor for suspicious hostname changes and restrict privileged access to systems that can modify the hostname.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-10030 — 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-2020-10030 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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- Version or environment caveats, and links to real fixes
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