CVE-2026-28413: Products.isurlinportal is a replacement for isURLInPortal method in Plone

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-28413 is a medium-severity flaw (CVSS 5.3) affecting isurlinportal. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 85%)
CISA exploited list	No
Weakness	CWE-601
Published	2026-03-05
Last modified	2026-06-17

Publisher (CNA): GitHub, Inc. · Vendor: plone

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-05 21:16 UTCPublished CVE record published
2026-06-17 10:28 UTCUpdated Record last modified

plone isurlinportal UPGRADE

Affected: < 2.1.0 · >= 3.0.0 and < 3.1.0 · 4.0.0 alpha1

Fixed in: 2.1.0, 3.1.0

Safe to downgrade to: a release before 3.0.0

1. Check installed version

apt-cache policy isurlinportal || rpm -q isurlinportal || isurlinportal --version

2. UPGRADE to 2.1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade isurlinportal

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade isurlinportal

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)

apt-cache madison isurlinportal sudo apt install isurlinportal=<VERSION_BEFORE_3.0.0> sudo apt-mark hold isurlinportal

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list isurlinportal sudo dnf downgrade isurlinportal-<VERSION_BEFORE_3.0.0> sudo dnf versionlock add isurlinportal

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-28413?

isurlinportal: upgrade to 2.1.0, 3.1.0. Exact commands for each OS are on this page.

Is CVE-2026-28413 being exploited?

CVE-2026-28413 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-28413 affect?

CVE-2026-28413 affects isurlinportal. Severity is medium (CVSS 5.3). 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 ve

How urgent is CVE-2026-28413?

Priority 27/100. Remotely exploitable, no login, no user action

References

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