CVE-2020-5765
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 8.10.0 and earlier were found to contain a Stored XSS vulnerability due to improper validation of input during scan configuration. An authenticated, remote attacker could potentially exploit this vulnerability to execute arbitrary code in a user's session. Tenable has implemented additional input validation mechanisms to correct this issue in Nessus 8.11.0.
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 confidenceNessus versions 8.10.0 and earlier contain a stored XSS vulnerability in the scan configuration functionality. The vulnerability stems from improper validation of user input during scan configuration, allowing an authenticated remote attacker to inject malicious scripts that execute within other users' sessions, potentially leading to 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<= 8.10.0CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
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 Nessus installation versionAccess the Nessus web interface and navigate to the 'About' page (click your username in the top-right corner), or run 'nessuscli --version' from the command line on the Nessus hostAffected if The reported version is 8.10.0 or earlier (e.g., 8.10.0, 8.9.1, 8.9.0, etc.)
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Identify existing scan configurationsLog into the Nessus web interface and navigate to 'Scans' > 'Policies' to list all saved scan policy templates created by usersAffected if Any scan policies exist that were created or modified by untrusted users, especially those containing unusual field values
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Inspect scan policy names for suspicious contentReview the names of all scan policies in the Policies list for unexpected characters, HTML tags, or script-like syntax (e.g., <script>, onerror=, javascript:)Affected if Any scan policy name contains HTML or JavaScript code that was not intentionally entered by an administrator
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Review custom scan policy fieldsOpen each custom scan policy by clicking on it and inspect all text fields (descriptions, plugin settings, credentials names) for injected contentAffected if Any text field displays raw HTML tags when viewed or renders differently than expected when the policy is opened
You are affected if Nessus is at version 8.10.0 or earlier and any scan policies contain unexpected HTML, JavaScript, or suspicious content injected by another authenticated user.
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 to Nessus 8.11.0 or later, which includes additional input validation mechanisms to correct this vulnerability. As a defense-in-depth measure, enforce strict session controls and monitor for suspicious scan configurations.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-5765 — 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-2020-5765 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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