CVE-2026-34587CWE-1336

Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering

High · published April 24, 2026

CVSS v4.0
7.6
EPSS
0%
Percentile
40.2
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
7.6 · HIGH
Vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
EPSS
0.00477 · 40.2th percentile
Weakness
CWE-1336 · Improper Neutralization of Special Elements Used in a Template Engine
Published
2026-04-24T00:23Z
EPSS history
Timeline
  • 24 APR 00:23Z
    Kirby has Server-Side Template Injection (SSTI) via double template resolution in option rendering
    cvelistv5