CVE-2020-28949
Published: August 25, 2022
Official Description
PEAR Archive_Tar allows an unserialization attack because phar: is blocked but PHAR: is not blocked. 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.
CISA KEV Advisory
PEAR Archive_Tar Deserialization of Untrusted Data Vulnerability
PEAR Archive_Tar allows an unserialization attack because phar: is blocked but PHAR: is not blocked. 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.
Apply updates per vendor instructions.
Risk Analysis
PEAR Archive_Tar is susceptible to an unserialization attack due to an incomplete block of the PHAR: protocol wrapper. This vulnerability can be exploited to achieve remote code execution. The high EPSS score of 0.92961 indicates a very high likelihood of exploitation, making this a critical vulnerability for systems using PEAR Archive_Tar.
This vulnerability is actively exploited in the wild and is listed in CISA's KEV catalog, confirming its use by malicious actors. The remote nature of the vulnerability makes it a significant threat.
Users of PEAR Archive_Tar, including those using third-party products like Drupal Core and Red Hat Linux, should apply available patches or updates. Ensure PHP configurations restrict deserialization of untrusted data.
Technical Analysis
CVE-2020-28949 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2020-28949 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (2)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2020-28949 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1