CVE-2021-36720
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 · uneditedPineApp - Mail Secure - Attacker sending a request to :/blocking.php?url=<script>alert(1)</script> and stealing cookies .
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 confidenceReflected cross-site scripting (XSS) vulnerability in PineApp Mail Secure's /blocking.php endpoint. The 'url' parameter accepts unsanitized user input which is reflected back in the response, allowing injection of malicious JavaScript (<script>alert(1)</script>) to execute in victim browsers and steal session cookies.
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< 5.2.1CVSS 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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Confirm PineApp Mail Secure is installedLocate PineApp Mail Secure installation directory or check for the product via system inventory, package manager, or web server configuration files that reference PineApp.Affected if PineApp Mail Secure is present in the environment
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Identify installed versionCheck version information from PineApp Mail Secure installation, typically found in version files, admin interface, or product metadata.Affected if The installed version is lower than 5.2.1
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Verify blocking.php endpoint existsCheck if /blocking.php exists in the web root or accessible paths of the PineApp Mail Secure installation.Affected if The blocking.php endpoint is present and accessible via the web server
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Test url parameter for reflected inputSend a crafted request to /blocking.php with a test value in the url parameter (e.g., url=test123) and examine if the value is reflected in the response without sanitization or encoding.Affected if The url parameter reflects user-supplied input directly in the HTML response without validation or escaping
The environment is affected if PineApp Mail Secure version is below 5.2.1 and the /blocking.php endpoint reflects the url parameter 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.
dbcve · scoped5.2.1
Implement proper input validation and output encoding for the url parameter in blocking.php. Use allowlist validation for expected URL formats and apply context-appropriate escaping before rendering any user-supplied data in HTML output.
Mail Secure version 5.2.1 or later
- 1. Verify current Mail Secure version by checking the system administration console or using the built-in version check command
- 2. Schedule a maintenance window for the upgrade process
- 3. Back up the current Mail Secure configuration and database according to standard backup procedures
- 4. Download Mail Secure version 5.2.1 or later from the official vendor distribution channel
- 5. Apply the upgrade following the vendor's documented upgrade procedure for Mail Secure
- 6. After upgrade completion, verify the blocking.php endpoint now properly sanitizes the url parameter
- 7. Test that the XSS payload <script>alert(1)</script> is no longer executable in the url parameter
- 8. Verify all other Mail Secure functions are operating normally
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 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-2021-36720 — 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-2021-36720 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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