Known exploited · PEAR

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

What it is

PEAR Archive_Tar Tar.php allows write operations with directory traversal due to inadequate checking of symbolic links. PEAR stands for PHP Extension and Application Repository and it is an open-source framework and distribution system for reusable PHP components with known usage in third-party products such as Drupal Core and Red Hat Linux.

Added August 25, 2022Due September 15, 2022CISA KEV catalog 2026.10.01

Vendor: PEAR
Product: Archive_Tar
Added to KEV: August 25, 2022
CISA due date: September 15, 2022
Ransomware use: Unknown
Weakness: CWE-22: Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'), CWE-59: Improper Link Resolution Before File Access ('Link Following')

What CISA requires

Apply updates per vendor instructions.

Forensic triage

What to do now

Find every instance of Archive_Tar you run, including the forgotten ones, and check its version against the vendor advisory.
Apply the vendor's fix or mitigation, before September 15, 2022 if you are bound by CISA's deadline, sooner if it faces the internet.
Assume it was tried against you already: look for signs of exploitation from the date it was added, not from the day you patched.
Until every instance is patched, block the attack at the edge: a WAF in blocking mode stops path traversal attempts.

References

CVE-2020-36193 in the National Vulnerability Database

The Dome

Block it at the edge while you patch

The Dome's WAF runs the OWASP Core Rule Set in blocking mode and stops path traversal attempts before they reach your application.

See the Dome

T Academy

Train the engineers who fix it

Security engineering on real hosts in the browser, every objective checked on the machine. The first two lessons of Linux 1 are free.

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Source: CISA Known Exploited Vulnerabilities Catalog (public domain), catalog version 2026.10.01.