CVE-2021-20079
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 · uneditedNessus versions 8.13.2 and earlier were found to contain a privilege escalation vulnerability which could allow a Nessus administrator user to upload a specially crafted file that could lead to gaining administrator privileges on the Nessus host.
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 confidenceNessus versions 8.13.2 and earlier contain a privilege escalation vulnerability where an authenticated Nessus administrator can upload a specially crafted file to gain elevated (administrator) privileges on the Nessus host itself, not just within the Nessus application.
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<= 8.13.2CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:H/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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Determine installed Nessus versionAccess the Nessus web interface (port 8834) and view the About page, or run 'nessuscli --version' from the command line, or check via your system's package manager (rpm -q nessus or dpkg -l nessus)Affected if The installed version is 8.13.2 or earlier
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Confirm Nessus administrator authentication existsVerify you have valid credentials for a Nessus administrator account, or review access logs for administrator-level sessionsAffected if An authenticated Nessus administrator account exists in the environment
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Check for file upload capabilityReview Nessus configuration and plugin upload settings accessible to administrator accounts, or audit audit logs for file upload API calls to /upload endpointsAffected if Nessus administrators can upload files or plugins to the system
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Review for suspicious file uploads or privilege escalation artifactsExamine Nessus server logs and file system for unexpected files in plugin directories (/opt/nessus/lib/nessus/plugins/ on Linux, similar paths on Windows), and check for new administrator accounts created on the hostAffected if Unexpected files in plugin directories or new local administrator accounts appear on the Nessus host
You are affected if Nessus version 8.13.2 or earlier is installed AND an authenticated administrator can upload files to the Nessus server.
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 Nessus to a version newer than 8.13.2. Apply the principle of least privilege to Nessus administrator accounts and monitor administrative activities for suspicious file upload operations.
- Consultation2.0 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 $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20079 — 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-2021-20079 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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