CVE-2020-36193: PEAR Archive_Tar Improper Link Resolution Vulnerability

Vulnerability summary

CVE-2020-36193 is a high (CVSS 7.5) Path Traversal vulnerability in PEAR Archive_Tar. It is known to be exploited: CISA lists it, first on 25-08-2022. EPSS estimates a 70.59% chance of exploitation in the next 30 days, higher than 99.3% of scored vulnerabilities.

Timeline

1. 18-01-2021
   PublishedVulnerability first disclosed.
2. 25-08-2022
   Added to CISA KEVPEAR Archive_Tar Improper Link Resolution Vulnerability
3. 15-09-2022
   CISA remediation dueApply updates per vendor instructions.
4. 21-10-2025
   Last modifiedVulnerability information updated.

Description

Tar.php in Archive_Tar through 1.4.11 allows write operations with Directory Traversal due to inadequate checking of symbolic links, a related issue to CVE-2020-28948.

• CWE-22Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')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.
• CWE-59Improper Link Resolution Before File Access ('Link Following')The product attempts to access a file based on the filename, but it does not properly prevent that filename from identifying a link or shortcut that resolves to an unintended resource.