Kirby: Access to image files outside of the site root via path traversal in the media handling
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- Present
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| getkirby | kirby | before 4.9.5; 5.0.0 to before 5.5.2 | 4.9.5, 5.5.2 | Patch available | CNA |
| — | getkirby/cms (Packagist) | before 4.9.5 | 4.9.5 | Patch available | GHSA-6j4c-mgqr-qv76 |
| — | getkirby/cms (Packagist) | 5.0.0 to before 5.5.2 | 5.5.2 | Patch available | GHSA-6j4c-mgqr-qv76 |
- kirby Vendorgetkirby Affected before 4.9.5; 5.0.0 to before 5.5.2 Fixed in 4.9.5, 5.5.2 Patch available CNA
- getkirby/cms (Packagist) Vendor— Affected before 4.9.5 Fixed in 4.9.5 Patch available GHSA-6j4c-mgqr-qv76
- getkirby/cms (Packagist) Vendor— Affected 5.0.0 to before 5.5.2 Fixed in 5.5.2 Patch available GHSA-6j4c-mgqr-qv76
Remediation
- Fix · CNA kirby (getkirby) Fixed in 4.9.5, 5.5.2
- Fix · GHSA-6j4c-mgqr-qv76 getkirby/cms (Packagist) Fixed in 4.9.5 Advisory →
- Fix · GHSA-6j4c-mgqr-qv76 getkirby/cms (Packagist) Fixed in 5.5.2 Advisory →
Timeline
- 2026-10-02 Threatist record created from CVE-2026-75592
- 2026-10-03 Alias added: GHSA-6j4c-mgqr-qv76
References
Other 6
- https://github.com/getkirby/kirby/security/advisories/GHSA-6j4c-mgqr-qv76
- https://github.com/getkirby/kirby/commit/2b6fab950bc89d505ea89576bf71c8de614cc3b2
- https://github.com/getkirby/kirby/commit/e0dca5f709adc21b36f5549df2c0619bc59da56c
- https://github.com/getkirby/kirby/releases/tag/4.9.5
- https://github.com/getkirby/kirby/releases/tag/5.5.2
- https://github.com/getkirby/kirby
More getkirby vulnerabilities
- TI-2024-17440 An arbitrary file upload vulnerability in the Profile Image module of Kirby CMS v4.1.0… CVSS 3.1HIGH 8.8
- TI-2024-17439 An HTML injection vulnerability exists in the Edit Content Layout module of Kirby CMS… CVSS 3.1HIGH 7.1
- TI-2026-23396 Kirby CMS through 5.1.4 allows an authenticated user with 'Editor' permissions to cause a… CVSS 3.1MEDIUM 6.5
- TI-2024-17441 A stored cross-site scripting (XSS) vulnerability in the Edit Content Layout module of… CVSS 3.1MEDIUM 6.1
- TI-2018-10413 An issue was discovered in Kirby 2.5.12. CVSS 3.1MEDIUM 5.4
- TI-2024-17438 Kirby CMS v4.1.0 was discovered to contain a reflected self-XSS vulnerability via the URL parameter. CVSS 3.1MEDIUM 4.7
Sources
- CVE-2026-75592 · CVE Program
- CVE-2026-75592 · NVD
- FIRST EPSS
- GHSA-6j4c-mgqr-qv76 · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences