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XSS via malicious Portal preview links

High
kevinansfield published GHSA-gv6q-2m97-882h Jan 27, 2026

Package

npm @tryghost/portal (npm)

Affected versions

2.29.1-2.51.4, 2.52.0-2.57.0

Patched versions

2.51.5, 2.57.1
npm ghost (npm)
5.43.0-5.120.4, 6.0.0-6.14.0
5.121.0, 6.15.0

Description

Impact

An attacker was able to craft a malicious link that, when accessed by an authenticated staff user or member, would execute JavaScript with the victim's permissions, potentially leading to account takeover.

Vulnerable versions

This vulnerability is present in Ghost versions:

  • v5.43.0 to v5.120.4
  • v6.0.0 to v6.14.0

As well as in Portal versions:

  • v2.29.1 to v2.51.4
  • v2.52.0 to v2.57.0

Patches

Ghost automatically loads the latest patch of the members Portal component via CDN. Therefore:

  • For Ghost 5.x users, upgrading to v5.121.0 or later fixes the vulnerability (loads Portal v2.51.5, which contains the patch)
  • For Ghost 6.x users, upgrading to v6.15.0 or later fixes the vulnerability (loads Portal v2.57.1, which contains the patch)

For Ghost installations using a customised or self-hosted version of Portal, it will be necessary to manually rebuild from or update to the latest patch version.

References

We thank Younes Belalia for discovering and disclosing this vulnerability responsibly.

For more information

If you have any questions or comments about this advisory, email us at security@ghost.org.

Severity

High

CVSS overall score

This score calculates overall vulnerability severity from 0 to 10 and is based on the Common Vulnerability Scoring System (CVSS).
/ 10

CVSS v3 base metrics

Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS v3 base metrics

Attack vector: More severe the more the remote (logically and physically) an attacker can be in order to exploit the vulnerability.
Attack complexity: More severe for the least complex attacks.
Privileges required: More severe if no privileges are required.
User interaction: More severe when no user interaction is required.
Scope: More severe when a scope change occurs, e.g. one vulnerable component impacts resources in components beyond its security scope.
Confidentiality: More severe when loss of data confidentiality is highest, measuring the level of data access available to an unauthorized user.
Integrity: More severe when loss of data integrity is the highest, measuring the consequence of data modification possible by an unauthorized user.
Availability: More severe when the loss of impacted component availability is highest.
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVE ID

CVE-2026-24778

Weaknesses

Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. Learn more on MITRE.