Kirby: Access to image files outside of the site root via path traversal in the media handling

Description

Kirby is an open-source content management system. Prior to 4.9.5 and 5.5.2, depending on the release line, Kirby's media handler used incomplete filesystem containment checks in src/Filesystem/Dir.php and src/Filesystem/F.php through Kirby\Filesystem\Dir::realpath() and Kirby\Filesystem\F::realpath(). The checks accepted a sibling directory whose path shared the intended root's string prefix, such as /var/www/site2 next to /var/www/site, because they did not require an exact match or a DIRECTORY_SEPARATOR boundary. A remote attacker could use Kirby\Cms\Media::thumb() to create and access thumbnails from image files in a PHP-readable sibling directory when that directory contained a valid .json thumbnail job file, potentially exposing staging sites, backups, or other internal sites and deleting the job file during processing. This issue is fixed in versions 4.9.5 and 5.5.2.

Scores

EPSS (exploitation in 30 days)

0.68% · top 48% of all CVEs (6 Nov 2026)

CISA SSVC

Exploitation: none · Automatable: no · Technical impact: partial

The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.9.

Weakness

• CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') (opens in a new tab)All about CWE-22 and its CVEs

Affected products

• getkirby · kirby

  • affected < 4.9.5
  • affected >= 5.0.0, < 5.5.2

Affected packages

From reviewed advisories of the GitHub Advisory Database.

• Packagistgetkirby/cmsGHSA-6j4c-mgqr-qv76 (opens in a new tab)

References (5)

• https://github.com/getkirby/kirby/security/advisories/GHSA-6j4c-mgqr-qv76 (opens in a new tab)x_refsource_CONFIRM
• https://github.com/getkirby/kirby/commit/2b6fab950bc89d505ea89576bf71c8de614cc3b2 (opens in a new tab)x_refsource_MISC
• https://github.com/getkirby/kirby/commit/e0dca5f709adc21b36f5549df2c0619bc59da56c (opens in a new tab)x_refsource_MISC
• https://github.com/getkirby/kirby/releases/tag/4.9.5 (opens in a new tab)x_refsource_MISC
• https://github.com/getkirby/kirby/releases/tag/5.5.2 (opens in a new tab)x_refsource_MISC

Sources

The same CVE in the primary databases and aggregators, to check against.

• CVE.org record (opens in a new tab)
• CVE List JSON (GitHub) (opens in a new tab)
• NVD (opens in a new tab)
• FIRST EPSS (opens in a new tab)
• OSV.dev (opens in a new tab)
• GitHub Advisory GHSA-6j4c-mgqr-qv76 (opens in a new tab)
• CIRCL Vulnerability-Lookup (opens in a new tab)

Badge for a README or a ticket

[![CVE-2026-75592](https://trackcve.app/badge/CVE-2026-75592.svg)](https://trackcve.app/cve/CVE-2026-75592)

Record last updated 1 Sept 2026, 13:41 UTC.