CVE-2026-35605
Published: 07 April 2026
Summary
CVE-2026-35605 is a medium-severity Path Traversal (CWE-22) vulnerability in Filebrowser Filebrowser. Its CVSS base score is 6.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 8.8th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified are NIST 800-53 AC-3 (Access Enforcement) and SI-10 (Information Input Validation).
Deeper analysis
CVE-2026-35605 is a vulnerability in File Browser, an open-source file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. In versions prior to 2.63.1, the Matches() function in rules/rules.go uses strings.HasPrefix() without a trailing directory separator when evaluating paths against access rules. This causes a rule intended for /uploads to also match paths like /uploads_backup/, potentially granting or denying access to unintended directories. Published on 2026-04-07, the issue carries a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N) and maps to CWE-22 (Improper Limitation of a Pathname to a Restricted Directory).
Remote unauthenticated attackers can exploit this flaw over the network with low complexity and no user interaction. By leveraging ambiguously matched paths, they can bypass intended access controls, gaining unauthorized permissions to perform file operations such as uploading, deleting, previewing, renaming, or editing in directories outside the rule's scope, resulting in high integrity impact without affecting confidentiality or availability.
The vulnerability is addressed in File Browser 2.63.1. Security advisories recommend upgrading to this patched version immediately. Additional details are available in the GitHub security advisory (GHSA-5q48-q4fm-g3m6) and the corresponding pull request (#5889).
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19778
Vulnerability details
File Browser is a file managing interface for uploading, deleting, previewing, renaming, and editing files within a specified directory. Prior to 2.63.1, the Matches() function in rules/rules.go uses strings.HasPrefix() without a trailing directory separator when matching paths against access rules.…
more
A rule for /uploads also matches /uploads_backup/, granting or denying access to unintended directories. This vulnerability is fixed in 2.63.1.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
The vulnerability allows remote unauthenticated attackers to bypass path access rules in a public-facing file management web application, directly enabling exploitation of the public-facing application for unauthorized file operations.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Enforces approved authorizations for logical access to information and system resources, directly addressing the flawed path matching that bypassed intended directory access controls.
Validates information inputs such as pathnames to ensure they adhere to restrictions, mitigating improper prefix matching without directory separators that allowed access to unintended directories.
Requires identification, reporting, and correction of system flaws like the access control bypass in File Browser's rules matching function, ensuring timely patching to version 2.63.1.