An editor with full access to the Kirby Panel can upload a PHP .phar
file and execute it on the server. This vulnerability is critical if you might have potential attackers in your group of authenticated Panel users, as they can gain access to the server with such a Phar file.
Visitors without Panel access cannot use this attack vector.
The problem has been patched in Kirby 2.5.14 and Kirby 3.4.5. Please update to one of these or a later version to fix the vulnerability.
Note: Kirby 2 reaches end of life on December 31, 2020. We therefore recommend to upgrade your Kirby 2 sites to Kirby 3. If you cannot upgrade, we still recommend to update to Kirby 2.5.14.
Kirby 2 sites on older releases can also be patched by applying the changes from this commit.
Thanks to Thore Imhof of Accenture for reporting the problem.
github.com/getkirby-v2/panel/commit/5a569d4e3ddaea2b6628d7ec1472a3e8bc410881
github.com/getkirby/kirby
github.com/getkirby/kirby/commit/db8f371b13036861c9cc5ba3e85e27f73fce5e09
github.com/getkirby/kirby/releases/tag/3.4.5
github.com/getkirby/kirby/security/advisories/GHSA-g3h8-cg9x-47qw
nvd.nist.gov/vuln/detail/CVE-2020-26255
packagist.org/packages/getkirby/cms
packagist.org/packages/getkirby/panel