VulnerabilityPublished 5 Mar 2026

CVE-2026-28413: plone Products.isurlinportal · Open Redirect

Affects plone Products.isurlinportalSource CVE Database V5

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Not known to be exploited · CVSS 5.3 Medium · fixed in 4.0.0 : update plone Products.isurlinportal when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score

5.3Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.2% chance of exploitation in 30 days – higher than 14% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.0.0, 3.1.0, 2.1.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: None
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: None: There is no loss of integrity within the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 5 Mar 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade Products.isurlinportal and plone/Products.isurlinportal to 4.0.0, 3.1.0 or 2.1.0.

Affected software

Product	Affected	Fixed in
ploneProducts.isurlinportal	Affected <4.0.0	Fixed in 4.0.0
ploneProducts.isurlinportal	Affected <3.1.0	Fixed in 3.1.0
ploneProducts.isurlinportal	Affected <2.1.0	Fixed in 2.1.0
GitHubplone/Products.isurlinportal`pkg:github/plone/Products.isurlinportal`Other threats	Affected <2.1.0 <3.1.0 <4.0.0	Fixed in 2.1.0 3.1.0 4.0.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-28413, organizations should promptly upgrade affected Plone Products.isurlinportal components to versions 2.1.0, 3.1.0, or 4.0.0 or later, where the open redirect flaw has been patched. In addition to patching, administrators should audit URL redirect handling configurations to ensure that only trusted internal URLs are allowed for redirection. Implement strict input validation and sanitization on all URL parameters related to redirection, enforcing whitelist policies that restrict redirects to known safe domains within the portal. Employ web application firewalls (WAFs) with rules designed to detect and block open redirect attempts targeting the 'came_from' parameter. User education campaigns to raise awareness about phishing risks and suspicious URLs can reduce the likelihood of successful exploitation. Monitoring logs for unusual redirect patterns or spikes in login redirection requests can help detect exploitation attempts early. Finally, consider implementing multi-factor authentication (MFA) to reduce the impact of credential theft resulting from phishing facilitated by this vulnerability.

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.

Impact

The primary impact of CVE-2026-28413 is on user confidentiality and trust. By enabling open redirects, attackers can craft URLs that appear to originate from a legitimate Plone portal but redirect users to malicious external sites. This can facilitate phishing campaigns, credential theft, and distribution of malware. Organizations relying on affected Plone versions may see increased phishing risks targeting their users, potentially leading to compromised credentials or unauthorized access to sensitive systems. While the vulnerability does not directly compromise system integrity or availability, the indirect consequences of successful phishing attacks can be severe, including data breaches and reputational damage. The ease of exploitation without authentication or user interaction beyond clicking a link broadens the attack surface. However, the absence of known active exploits reduces immediate risk. Organizations with public-facing Plone portals, especially those in sectors like government, education, and healthcare, are particularly vulnerable due to the value of their user bases and the trust placed in their domains.

CWE-601URL Redirection to Untrusted Site (Open Redirect) (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design · Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.5 (opens in a new tab)
Attack patterns
Cross-Site Flashing (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

github.com/plone/Products.isurlinportal/security/advisories/GHSA-43gx-6gv6-3jcp (opens in a new tab)

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Mar 2026, 20:31 UTC

WeaknessesCWE-601

Technical details

References

Community reviews

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