CVE-2021-44541
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 · uneditedA vulnerability was found in Privoxy which was fixed in process_encrypted_request_headers() by freeing header memory when failing to get the request destination.
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 confidencePrivoxy contains a memory handling vulnerability in process_encrypted_request_headers() where header memory is incorrectly freed when the function fails to get the request destination. This improper memory free operation can lead to double-free or use-after-free conditions, potentially allowing denial of service or potentially remote 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< 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
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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 Privoxy is installedRun 'privoxy --version' or check for the privoxy binary at /usr/sbin/privoxy or /usr/local/sbin/privoxyAffected if Privoxy is not found on the system - not applicable
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Determine installed Privoxy versionRun 'privoxy --version' and note the version number displayedAffected if The version shown is lower than 3.0.33 (for example, 3.0.32, 3.0.31, etc.)
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Locate Privoxy configuration fileCommon locations: /etc/privoxy/config, /usr/local/etc/privoxy/config, or check /etc/privoxy/ directory for config filesAffected if Configuration file exists and Privoxy version is below 3.0.33
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Verify encrypted request headers processing is in useSearch the Privoxy configuration file for directives related to HTTPS/proxy handling, such as 'enable-https-interception' or 'handle-escd', or check if Privoxy is configured as a forward proxy handling encrypted trafficAffected if Privoxy is configured to process encrypted (HTTPS) requests and the version is below 3.0.33
The system is affected if Privoxy is installed with a version lower than 3.0.33 and is configured to handle encrypted request headers or act as a proxy for HTTPS traffic.
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
Upgrade Privoxy to the version containing the fix for process_encrypted_request_headers(). If upgrading is not immediately possible, restrict access to the Privoxy service to trusted users to reduce the attack surface.
Privoxy 3.0.33
- 1. Check the currently installed Privoxy version (e.g., privoxy --version or privoxy -v)
- 2. Download Privoxy version 3.0.33 from the official Privoxy website (www.privoxy.org)
- 3. Install the new version using your system's package manager or by compiling from source
- 4. Verify the installation was successful by checking the version again
- 5. Restart the Privoxy service to apply the update
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing4.0 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 $3,328.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-44541 — 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-2021-44541 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
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