YOURLS is a self-hosted, customizable URL shortener written in PHP. Prior to 1.10.5, yourls_get_request() extracted the request path without sanitization, after which yourls_sanitize_url() and yourls_esc_url() preserved dot and slash traversal sequences before an attacker-controlled keyword reached file_exists() and include() under YOURLS_PAGEDIR. An unauthenticated remote attacker could traverse outside the intended pages directory and include a local PHP file that was already present on the server, such as an uploaded or injected file, causing the file to execute in the YOURLS web process.
This issue is fixed in version 1.10.5.
Attack Parameters
Attack Vector
Local
Requires local access
Attack Complexity
Low
Easy to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
Low
Partial data leak
Integrity
Low
Partial data modification
Availability
Low
Partial disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 4
https://github.com/YOURLS/YOURLS/commit/4e85972160a96e03a419a442d5bd8f21f2f02ddb
security-advisories@github.com
https://github.com/YOURLS/YOURLS/pull/4142
security-advisories@github.com
https://github.com/YOURLS/YOURLS/releases/tag/1.10.5
security-advisories@github.com
https://github.com/YOURLS/YOURLS/security/advisories/GHSA-f8ff-652m-j5rx
security-advisories@github.com