{"id":"CVE-2017-9233","title":"XML External Entity vulnerability in libexpat 2.2.0 and earlier (Expat XML Parser Library) allows attackers to put the parser in an infinite loop using a malformed external entity definition from an external DTD.","summary":"XML External Entity vulnerability in libexpat 2.2.0 and earlier (Expat XML Parser Library) allows attackers to put the parser in an infinite loop using a malformed external entity definition from an external DTD.","severity":"high","cvss":7.5,"cvssVector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","cwe":["CWE-611","CWE-835"],"vendor":"libexpat_project","product":"libexpat","affected":["libexpat <= 2.2.0","python >= 2.7.0, < 2.7.15","python >= 3.3.0, < 3.3.7","python >= 3.4.0, < 3.4.7","python >= 3.5.0, < 3.5.4","python >= 3.6.0, < 3.6.2","debian_linux = 8.0","debian_linux = 9.0","debian_linux = 10.0"],"patched":["python 3.6.2"],"published":"2017-07-25","updated":"2026-10-08","sourceUpdated":"2026-10-08T21:17:06.167","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2017-9233","references":[{"url":"http://www.debian.org/security/2017/dsa-3898","label":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2017/06/17/7","label":"cve@mitre.org"},{"url":"http://www.securityfocus.com/bid/99276","label":"cve@mitre.org"},{"url":"http://www.securitytracker.com/id/1039427","label":"cve@mitre.org"},{"url":"https://github.com/libexpat/libexpat/blob/master/expat/Changes","label":"cve@mitre.org"},{"url":"https://libexpat.github.io/doc/cve-2017-9233/","label":"cve@mitre.org"},{"url":"https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E","label":"cve@mitre.org"},{"url":"https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E","label":"cve@mitre.org"},{"url":"https://support.apple.com/HT208112","label":"cve@mitre.org"},{"url":"https://support.apple.com/HT208113","label":"cve@mitre.org"},{"url":"https://support.apple.com/HT208115","label":"cve@mitre.org"},{"url":"https://support.apple.com/HT208144","label":"cve@mitre.org"},{"url":"https://support.f5.com/csp/article/K03244804","label":"cve@mitre.org"},{"url":"http://www.debian.org/security/2017/dsa-3898","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2017/06/17/7","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/99276","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1039427","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://github.com/libexpat/libexpat/blob/master/expat/Changes","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://libexpat.github.io/doc/cve-2017-9233/","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/HT208112","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/HT208113","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/HT208115","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.apple.com/HT208144","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://support.f5.com/csp/article/K03244804","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.08739,"epssPercentile":0.95047,"ingestedAt":"2026-10-08T22:11:53.692Z","slug":"CVE-2017-9233","body":"## Overview\n\nXML External Entity vulnerability in libexpat 2.2.0 and earlier (Expat XML Parser Library) allows attackers to put the parser in an infinite loop using a malformed external entity definition from an external DTD.\n\n## Affected\n\n- `libexpat <= 2.2.0`\n- `python >= 2.7.0, < 2.7.15`\n- `python >= 3.3.0, < 3.3.7`\n- `python >= 3.4.0, < 3.4.7`\n- `python >= 3.5.0, < 3.5.4`\n- `python >= 3.6.0, < 3.6.2`\n- `debian_linux = 8.0`\n- `debian_linux = 9.0`\n- `debian_linux = 10.0`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `python 3.6.2`","depth":"twilight","depthScore":43,"depthScoreParts":{"impact":41.3,"likelihood":1.7,"exploitation":0,"ransomware":0},"changes":[]}