CVE-2018-1000888

CVE-2018-1000888 is a high-severity vulnerability in Php Pear Archive Tar with a CVSS 3.x base score of 8.8. Its EPSS exploit-prediction score of 19% places it in the 97th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-502.

Key facts

Description

PEAR Archive_Tar version 1.4.3 and earlier contains a CWE-502, CWE-915 vulnerability in the Archive_Tar class. There are several file operations with `$v_header['filename']` as parameter (such as file_exists, is_file, is_dir, etc). When extract is called without a specific prefix path, we can trigger unserialization by crafting a tar file with `phar://[path_to_malicious_phar_file]` as path. Object injection can be used to trigger destruct in the loaded PHP classes, e.g. the Archive_Tar class itself. With Archive_Tar object injection, arbitrary file deletion can occur because `@unlink($this->_temp_tarname)` is called. If another class with useful gadget is loaded, it may possible to cause remote code execution that can result in files being deleted or possibly modified. This vulnerability appears to have been fixed in 1.4.4.

Frequently asked questions

What is CVE-2018-1000888?
PEAR Archive_Tar version 1.4.3 and earlier contains a CWE-502, CWE-915 vulnerability in the Archive_Tar class. There are several file operations with `$v_header['filename']` as parameter (such as file_exists, is_file, is_dir, etc). When extract is called without a specific prefix path, we can trigger unserialization by crafting a tar file with `phar://[path_to_malicious_phar_file]` as path. Object injection can be used to trigger destruct in the loaded PHP classes, e.g. the Archive_Tar class itself. With Archive_Tar object injection, arbitrary file deletion can occur because `@unlink($this->_temp_tarname)` is called. If another class with useful gadget is loaded, it may possible to cause remote code execution that can result in files being deleted or possibly modified. This vulnerability appears to have been fixed in 1.4.4.
How severe is CVE-2018-1000888?
CVE-2018-1000888 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-1000888 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 19% (97th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-1000888?
CVE-2018-1000888 primarily affects Php Pear Archive Tar. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-1000888?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-1000888 published?
CVE-2018-1000888 was published on 2018-12-28 and last updated on 2026-06-17.

References

Affected products (6)

Other CWE-502 (Deserialization of Untrusted Data) vulnerabilities

Browse all CWE-502 (Deserialization of Untrusted Data) vulnerabilities →