{"id":86441,"date":"2026-02-11T19:14:09","date_gmt":"2026-02-11T19:14:09","guid":{"rendered":""},"modified":"-0001-11-30T00:00:00","modified_gmt":"-0001-11-30T00:00:00","slug":"cve-2025-4435-improper-handling-of-filtered-files-in-archive-extraction","status":"publish","type":"post","link":"https:\/\/www.ameeba.com\/blog\/cve-2025-4435-improper-handling-of-filtered-files-in-archive-extraction\/","title":{"rendered":"CVE-2025-4435: Improper Handling of Filtered Files in Archive Extraction<\/strong>"},"content":{"rendered":"

Overview<\/strong><\/p>\n

CVE-2025-4435 is a critical vulnerability that stems from the improper handling of filtered files during the extraction of archives. This vulnerability affects a range of systems and applications that utilize TarFile for archive management, potentially leading to system compromise or data leakage. The issue arises when TarFile.errorlevel = 0 and extraction occurs with a filter, whereby the expectation is for filtered members to be skipped in the extraction process, but they are not.<\/p>\n

Vulnerability Summary<\/strong><\/p>\n

CVE ID: CVE-2025-4435
\nSeverity: High (CVSS: 7.5)
\nAttack Vector: Network
\nPrivileges Required: Low
\nUser Interaction: None
\nImpact: System compromise or Data leakage<\/p>\n

Affected Products<\/strong><\/p>\n

Product | Affected Versions<\/p>\n

TarFile | All versions prior to patch release
\nPython | Versions using affected TarFile library<\/p>\n

How the Exploit Works<\/strong><\/p>\n

The exploit takes advantage of the faulty behavior of TarFile.errorlevel = 0 during archive extraction. Instead of skipping the filtered members as expected, the vulnerability allows these members to be extracted. An attacker can exploit this by embedding malicious payloads in such filtered members. When the extraction process happens, the malicious payload is released into the system, potentially leading to system compromises or data leakage.<\/p>\n

Conceptual Example Code<\/strong><\/p>\n

Here is a conceptual example of how an attacker might exploit this vulnerability.<\/p>\n

# Create a tarfile with malicious payload\nimport tarfile\ntar = tarfile.open(\"exploit.tar\", \"w\")\ntar.add(\"malicious_payload\")\ntar.close()\n# Now, the tarfile is sent to the target system. On the target system, the following happens:\nimport tarfile\ntar = tarfile.open(\"exploit.tar\")\ntar.errorlevel = 0  # Expectation: malicious_payload should be skipped during extraction\ntar.extractall(path=\"target_directory\", members=filter_function)  # Actual: malicious_payload gets extracted\ntar.close()<\/code><\/pre>\n
In the above example, `filter_function` is intended to filter out `malicious_payload`, but due to the vulnerability, it is not skipped during extraction.<\/p>\n","protected":false},"excerpt":{"rendered":"
Overview CVE-2025-4435 is a critical vulnerability that stems from the improper handling of filtered files during the extraction of archives. This vulnerability affects a range of systems and applications that utilize TarFile for archive management, potentially leading to system compromise or data leakage. The issue arises when TarFile.errorlevel = 0 and extraction occurs with a […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"om_disable_all_campaigns":false,"_monsterinsights_skip_tracking":false,"footnotes":""},"categories":[],"tags":[],"vendor":[],"product":[],"attack_vector":[],"asset_type":[],"severity":[],"exploit_status":[],"class_list":["post-86441","post","type-post","status-publish","format-standard","hentry"],"aioseo_notices":[],"aioseo_head":"\n\t\t\n\t\n\t\n\t\n\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t\n\t\t