CVE-2021-43675
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 · uneditedLychee-v3 3.2.16 is affected by a Cross Site Scripting (XSS) vulnerability in php/Access/Guest.php. The function exit will terminate the script and print the message to the user. The message will contain albumID which is controlled by the user.
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 confidenceReflected XSS vulnerability in Lychee v3.2.16 where the user-controlled albumID parameter in php/Access/Guest.php is directly output through the exit() function without sanitization, allowing injection of arbitrary JavaScript.
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= 3.2.16CVSS 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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Identify Lychee installation versionLocate the Lychee installation directory and check the version file or composer.json to determine the installed version. Compare against the affected version 3.2.16.Affected if The installed version is exactly 3.2.16
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Verify Guest.php existsConfirm the file php/Access/Guest.php exists within the Lychee installation directory.Affected if The file php/Access/Guest.php is present in the installation
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Check if guest access is enabledExamine Lychee configuration settings (usually in config.php or database) to determine if guest/public access is enabled for albums.Affected if Guest access is enabled and unauthenticated users can access albums
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Inspect the vulnerable code patternOpen php/Access/Guest.php and search for the exit() function call that outputs the albumID parameter without htmlspecialchars() or similar sanitization.Affected if The code contains an exit() or similar output function that directly incorporates the albumID parameter without sanitization
You are affected if Lychee version is exactly 3.2.16, the Guest.php file exists, guest access is enabled, and the albumID parameter is reflected in the response without sanitization.
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 dataImplement input validation and output encoding for the albumID parameter before it is reflected in the response. Use htmlspecialchars() or equivalent encoding functions to neutralize script injection attempts.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-43675 — 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-2021-43675 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
- No spam, self-promotion, credentials, or personal data