CVE-2026-28413
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 · uneditedProducts.isurlinportal is a replacement for isURLInPortal method in Plone. Prior to versions 2.1.0, 3.1.0, and 4.0.0, a url /login?came_from=////evil.example may redirect to an external website after login. This issue has been patched in versions 2.1.0, 3.1.0, and 4.0.0.
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 Products.isurlinportal allows attackers to craft malicious login URLs (e.g., /login?came_from=////evil.example) that redirect authenticated users to external websites after login. The came_from parameter is not properly validated against the portal boundary, allowing attackers to bypass the intended portal-only redirect restriction.
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< 2.1.0>= 3.0.0, < 3.1.0= 4.0.0CVSS 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 installed Products.isurlinportal versionRun the package manager or check the installed version using pip (pip show Products.isurlinportal) or your Plone instance control panel to determine the exact version number installedAffected if The installed version is < 2.1.0, OR >= 3.0.0 and < 3.1.0, OR exactly 4.0.0
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Locate the isurlinportal module in your Plone installationFind the Products.isurlinportal package directory in your Plone instance (typically in the eggs or products folder) and examine the isurlinportal.py or __init__.py fileAffected if The isurlinportal module exists and handles URL redirects in your installation
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Check login form for came_from parameter handlingExamine your login form template or view (commonly login.pt or login.py in the Plone skins/products directory) to see if the came_from parameter is used to control post-login redirectionAffected if The login mechanism accepts and uses a came_from parameter for redirects
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Inspect URL validation logic in isurlinportalOpen the isurlinportal.py file and look for the function that validates redirect URLs. Check if it verifies that the target URL remains within the portal domain before allowing the redirectAffected if The code lacks proper validation ensuring the redirect URL stays within the portal boundary
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Test the vulnerable redirect behaviorIf you have a test environment, attempt a login with a came_from parameter set to an external domain (e.g., /login?came_from=////evil.example) and observe if the application redirects to the external site after authenticationAffected if After login, the user is redirected to an external domain rather than remaining within the portal
You are affected if Products.isurlinportal is installed at a version matching < 2.1.0, >= 3.0.0 and < 3.1.0, or exactly 4.0.0 AND your login flow uses the came_from parameter for post-login redirects.
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 · scoped2.1.03.1.0
Upgrade Products.isurlinportal to version 2.1.0, 3.1.0, or 4.0.0 (whichever is compatible with the Plone version). The patch adds proper validation of the redirect URL to ensure it remains within the portal domain.
Upgrade to version 2.1.0 (for <2.1.0 branch), 3.1.0 (for 3.0.x branch), or the latest 4.x release (for 4.0.0 branch)
- Identify the current version of the isurlinportal package in your project
- Determine which version branch your installation is on (< 2.1.0, between 3.0.0-3.0.x, or 4.0.0)
- Run pip install --upgrade isurlinportal to upgrade to the latest version
- For version branch < 2.1.0: upgrade to version 2.1.0 or later
- For version branch >= 3.0.0, < 3.1.0: upgrade to version 3.1.0 or later
- For version 4.0.0: confirm the installed version includes the security patch (4.0.0 or later)
- Verify the fix by testing that URLs like /login?came_from=////evil.example no longer redirect to external domains
- Rebuild and redeploy your application with the updated dependency
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
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-28413 — 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-2026-28413 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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- Version or environment caveats, and links to real fixes
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