7.6
HIGH CVSS 4.0
CVE-2026-34587
Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering
Description

Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions. For pages, Kirby provides the `pages.create` and `pages.changeStatus` permissions (among others). In affected releases, Kirby checked these permissions independently and only for the respective action. However the `changeStatus` permission didn't take effect on page creation. New pages are created as drafts by default and need to be published by changing the page status of an existing page draft. This is ensured when the page is created via the Kirby Panel. However the REST API allows to override the `isDraft` flag when creating a new page. This allowed authenticated attackers with the `pages.create` permission to immediately create published pages, bypassing the normal editorial workflow. The problem has been patched in Kirby 4.9.0 and Kirby 5.4.0. Kirby has updated the `Options` logic to no longer double-resolve queries in option values coming from `OptionsQuery` or `OptionsApi` sources. Kirby now only resolves queries that are directly configured in the blueprints.

INFO

Published Date :

April 24, 2026, 1:16 a.m.

Last Modified :

April 24, 2026, 1:16 a.m.

Remotely Exploit :

Yes !
Affected Products

The following products are affected by CVE-2026-34587 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 HIGH [email protected]
Solution
Update Kirby CMS to versions 4.9.0 or 5.4.0 to fix authorization bypass.
  • Update Kirby CMS to version 4.9.0 or later.
  • Update Kirby CMS to version 5.4.0 or later.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-34587.

URL Resource
https://github.com/getkirby/kirby/releases/tag/4.9.0
https://github.com/getkirby/kirby/releases/tag/5.4.0
https://github.com/getkirby/kirby/security/advisories/GHSA-jcjw-58rv-c452
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-34587 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-34587 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-34587 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-34587 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Apr. 24, 2026

    Action Type Old Value New Value
    Added Description Kirby is an open-source content management system. Prior to versions 4.9.0 and 5.4.0, Kirby's user permissions control which user role is allowed to perform specific actions to content models in the CMS. These permissions are defined for each role in the user blueprint (`site/blueprints/users/...`). It is also possible to customize the permissions for each target model in the model blueprints (such as in `site/blueprints/pages/...`) using the `options` feature. The permissions and options together control the authorization of user actions. For pages, Kirby provides the `pages.create` and `pages.changeStatus` permissions (among others). In affected releases, Kirby checked these permissions independently and only for the respective action. However the `changeStatus` permission didn't take effect on page creation. New pages are created as drafts by default and need to be published by changing the page status of an existing page draft. This is ensured when the page is created via the Kirby Panel. However the REST API allows to override the `isDraft` flag when creating a new page. This allowed authenticated attackers with the `pages.create` permission to immediately create published pages, bypassing the normal editorial workflow. The problem has been patched in Kirby 4.9.0 and Kirby 5.4.0. Kirby has updated the `Options` logic to no longer double-resolve queries in option values coming from `OptionsQuery` or `OptionsApi` sources. Kirby now only resolves queries that are directly configured in the blueprints.
    Added CVSS V4.0 AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-1336
    Added Reference https://github.com/getkirby/kirby/releases/tag/4.9.0
    Added Reference https://github.com/getkirby/kirby/releases/tag/5.4.0
    Added Reference https://github.com/getkirby/kirby/security/advisories/GHSA-jcjw-58rv-c452
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.