CVE-2026-42207
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 · uneditedMagento Long Term Support (LTS) is an unofficial, community-driven project provides an alternative to the Magento Community Edition e-commerce platform with a high level of backward compatibility. Prior to 20.18.0, Mage_ProductAlert_AddController::stockAction() reads the uenc query parameter and passes it directly to $this->_redirectUrl($backUrl) without calling $this->_isUrlInternal(). When the supplied product_id does not match any catalog product, the server issues an unvalidated HTTP 302 redirect to whatever URL was provided as uenc. This vulnerability is fixed in 20.18.0.
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 confidenceOpen redirect vulnerability in Magento LTS where the stockAction() controller reads the uenc query parameter and passes it directly to _redirectUrl() without validating it via _isUrlInternal(). When a product_id doesn't exist, the server issues an unvalidated HTTP 302 redirect to attacker-controlled URLs.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
CVSS 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 Magento LTS versionCheck the version file in your Magento installation (typically composer.json or a version config file). Compare the installed version number to the affected range (versions prior to 20.18.0).Affected if Installed version is below 20.18.0
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Locate the stockAction controllerSearch for the file containing the stockAction() method in your Magento codebase. This is typically found in the adminhtml or inventory-related controllers.Affected if The stockAction() method exists and handles requests
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Verify uenc parameter handling in stockActionExamine the stockAction() controller code and look for direct usage of the 'uenc' query parameter being passed to _redirectUrl() without a validation call to _isUrlInternal().Affected if Code shows uenc parameter passed to _redirectUrl() without _isUrlInternal() validation
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Check product_id existence handlingReview the code flow in stockAction() to confirm that when a non-existent product_id is provided, the controller issues a redirect using the unvalidated uenc value.Affected if Redirect occurs with attacker-controlled URL when product_id doesn't exist
You are affected if your Magento LTS version is below 20.18.0 and the stockAction controller with uenc parameter handling is present and accessible.
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 · scopedUpgrade to Magento LTS version 20.18.0 or later, which implements proper URL validation using _isUrlInternal() before performing redirects.
20.18.0
- Upgrade Magento LTS to version 20.18.0 or later to include the fix that validates the uenc parameter before performing redirects
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,376.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42207 — 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-2026-42207 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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