CVE-2026-75594
Received Received - Intake

Path Traversal in Kirby CMS

Vulnerability report for CVE-2026-75594, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-31

Last updated on: 2026-08-31

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

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Meta Information

Published
2026-08-31
Last Modified
2026-08-31
Generated
2026-09-01
AI Q&A
2026-09-01
EPSS Evaluated
N/A
NVD

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
getkirby kirby 4.9.5
getkirby kirby 5.5.2
getkirby kirby to 4.9.5|end_excluding=5.5.2 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-22 The product uses external input to construct a pathname that is intended to identify a file or directory that is located underneath a restricted parent directory, but the product does not properly neutralize special elements within the pathname that can cause the pathname to resolve to a location that is outside of the restricted directory.

Attack-Flow Graph

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Executive Summary

Kirby CMS versions before 4.9.5 and 5.5.2 had a flaw in the media handler that allowed path traversal via encoded slashes (%2f) in filenames. This could let attackers access files outside the intended media directory on certain web servers like nginx or Apache with specific settings. The vulnerability also involved differences in error responses revealing file existence and a file deletion issue.

Impact Analysis

An attacker could exploit this to read sensitive files outside the media directory, such as configuration files or other stored data. They might also delete arbitrary files by manipulating thumbnail job files. This could lead to data leaks, unauthorized access, or service disruption if critical files are removed.

Compliance Impact

This vulnerability could lead to unauthorized access to sensitive data, violating GDPR's data protection principles or HIPAA's confidentiality requirements. A data breach resulting from this flaw may require notifications to authorities and affected individuals, leading to legal penalties and reputational damage.

Mitigation Strategies

Immediately upgrade Kirby to version 4.9.5 or 5.5.2 or later to patch the vulnerability. Disable AllowEncodedSlashes in Apache if enabled. Review media directory permissions to restrict unauthorized access.

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EPSS Chart