Summary
Archive_Tar contains Potential RCE if filename starts with phar://
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.
Impact
CVE-2018-1000888 has a CVSS score of 8.8 (High). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. A fixed version is available (1.4.4); upgrading removes the vulnerable code path.
Affected versions
Security releases
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
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Frequently Asked Questions
- What is CVE-2018-1000888? CVE-2018-1000888 is a high-severity security vulnerability in pear/archive_tar (composer), affecting versions < 1.4.4. It is fixed in 1.4.4.
- How severe is CVE-2018-1000888? CVE-2018-1000888 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
- Which versions of pear/archive_tar are affected by CVE-2018-1000888? pear/archive_tar (composer) versions < 1.4.4 is affected.
- Is there a fix for CVE-2018-1000888? Yes. CVE-2018-1000888 is fixed in 1.4.4. Upgrade to this version or later.
- Is CVE-2018-1000888 exploitable, and should I be worried? Whether CVE-2018-1000888 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2018-1000888 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2018-1000888? Upgrade
pear/archive_tarto 1.4.4 or later.