Nginx ControllerWeb server / proxy · F5
CVE-2020-5895
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 · uneditedOn NGINX Controller versions 3.1.0-3.3.0, AVRD uses world-readable and world-writable permissions on its socket, which allows processes or users on the local system to write arbitrary data into the socket. A local system attacker can make AVRD segmentation fault (SIGSEGV) by writing malformed messages to the socket.
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 confidenceIn NGINX Controller versions 3.1.0-3.3.0, the AVRD (likely related to authentication, validation, or reporting daemon) creates a Unix domain socket with overly permissive world-readable and world-writable permissions (777). This allows any local user or process to write arbitrary data to the socket, potentially corrupting AVRD's operation or causing a denial of service via SIGSEGV when malformed messages are sent.
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
Nginx ControllerWeb server / proxy
>= 3.1.0, < 3.4.0CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/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 installed NGINX Controller versionRun `nginx-controller -v` or check the package manager for the installed nginx-controller versionAffected if Version is 3.1.0 through 3.3.0 (or < 3.4.0)
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Identify AVRD processRun `ps aux | grep avrd` to confirm the AVRD daemon is runningAffected if AVRD process is running on the system
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Locate AVRD Unix socketFind Unix domain sockets owned by the avrd user using `find / -type s -user avrd 2>/dev/null` or inspect process file descriptors at `/proc/<avrd-pid>/fd`Affected if A Unix socket created by avrd exists on the system
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Verify socket permissionsUse `ls -la <socket-path>` to inspect the socket file permissionsAffected if Socket permissions show 777 (rwxrwxrwx) or similar world-readable/writable setting
You are affected if NGINX Controller version is between 3.1.0 and 3.3.0 inclusive AND the AVRD Unix socket exists with overly permissive (world-writable) permissions.
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 data3.4.0
Restrict socket permissions to the owner and group only (e.g., 660 or 770) or implement proper authentication/authorization on the socket to prevent unauthorized local access. Upgrade to version 3.3.1 or later if available.
Fix this in Nginx Controller
Scoped from the published advisory
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,408.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-5895 — 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-2020-5895 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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