CVE-2021-44543
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 XSS vulnerability was found in Privoxy which was fixed in cgi_error_no_template() by encode the template name when Privoxy is configured to servce the user-manual itself.
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 confidenceAn XSS vulnerability exists in Privoxy's cgi_error_no_template() function where the template name is not properly encoded when Privoxy is configured to serve its own user-manual. This allows an attacker to inject malicious script content through the template parameter.
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< 3.0.33CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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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Check Privoxy versionRun 'privoxy --version' or check your package manager for installed privoxy versionAffected if Installed version is lower than 3.0.33
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Locate Privoxy configuration fileFind the main config file (usually /etc/privoxy/config or /usr/local/etc/privoxy/config)Affected if Configuration file exists and is readable
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Verify if Privoxy serves its own user-manualSearch the configuration file for 'user-manual' or 'templat' directives. Look for lines containing 'cgi-error' or template paths pointing to Privoxy's built-in manualAffected if Configuration contains directives that enable Privoxy to serve its own user-manual (the vulnerable feature)
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Confirm the cgi_error function is accessibleCheck if the Privoxy server is running and accessible on its HTTP port. Test accessing a URL that would trigger the cgi_error_no_template() function with a template parameterAffected if Privoxy is running and the cgi-error functionality is accessible via HTTP
A user is affected if Privoxy version is below 3.0.33 AND Privoxy is configured to serve its own user-manual, exposing the cgi_error_no_template() function to XSS attacks via the template parameter.
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 · scoped3.0.33
Update Privoxy to the version that encodes template names in cgi_error_no_template(). If immediate update is not possible, avoid configuring Privoxy to serve its own user-manual.
3.0.33
- 1. Check the currently installed Privoxy version (e.g., privoxy --version)
- 2. Download Privoxy version 3.0.33 or later from the official Privoxy website (www.privoxy.org)
- 3. Backup your current Privoxy configuration files
- 4. Install the updated Privoxy package using your system's package manager or by compiling from source
- 5. Restore your backed-up configuration files
- 6. Restart the Privoxy service
- 7. Verify the installation by checking the version number
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-44543 — 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-2021-44543 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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