{"id":"CVE-2016-10033","aliases":["GHSA-5f37-gxvh-23v6"],"url":"https://o3.security/vulnerability/CVE-2016-10033","summary":"Remote code execution in PHPMailer","details":"### Impact\nThe `mailSend` function in the default `isMail` transport in PHPMailer before 5.2.18 might allow remote attackers to pass extra parameters to the mail command and consequently execute arbitrary code via a \\" (backslash double quote) in a crafted `Sender` property.\n\n### Patches\nFixed in 5.2.18\n\n### Workarounds\nFilter and validate user input before passing it to internal functions.\n\n### References\nhttps://nvd.nist.gov/vuln/detail/CVE-2016-10033\nRelated to a follow-on issue in https://nvd.nist.gov/vuln/detail/CVE-2016-10045\n\n### For more information\nIf you have any questions or comments about this advisory:\n* Open a private issue in [the PHPMailer project](https://github.com/PHPMailer/PHPMailer)","published":"2016-12-30T19:59:00.137Z","modified":"2026-10-24T10:46:19.745768974Z","cvss":{"score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"epss":{"score":0.99714,"percentile":0.99951,"asOf":"2026-09-10"},"cisaKev":null,"exploitsKnown":37,"affectedPackages":[{"ecosystem":"Packagist","name":"phpmailer/phpmailer","fixedVersion":"5.2.18"}],"fix":null,"references":[{"type":"WEB","url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2016-10033"},{"type":"ADVISORY","url":"http://www.securityfocus.com/archive/1/539963/100/0/threaded"},{"type":"ADVISORY","url":"http://www.securitytracker.com/id/1037533"},{"type":"ADVISORY","url":"https://developer.joomla.org/security-centre/668-20161205-phpmailer-security-advisory.html"},{"type":"ADVISORY","url":"https://www.drupal.org/psa-2016-004"},{"type":"FIX","url":"http://seclists.org/fulldisclosure/2016/Dec/78"},{"type":"FIX","url":"https://github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18"},{"type":"FIX","url":"https://github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045-vulnerabilities"},{"type":"FIX","url":"https://legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-Vuln.html"},{"type":"FIX","url":"https://www.exploit-db.com/exploits/40968/"},{"type":"FIX","url":"https://www.exploit-db.com/exploits/40970/"},{"type":"EVIDENCE","url":"http://packetstormsecurity.com/files/140291/PHPMailer-Remote-Code-Execution.html"},{"type":"EVIDENCE","url":"http://packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html"},{"type":"EVIDENCE","url":"http://www.rapid7.com/db/modules/exploit/multi/http/phpmailer_arg_injection"},{"type":"EVIDENCE","url":"http://www.securityfocus.com/bid/95108"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/40969/"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/40974/"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/40986/"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/41962/"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/41996/"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/42024/"},{"type":"EVIDENCE","url":"https://www.exploit-db.com/exploits/42221/"},{"type":"WEB","url":"https://github.com/PHPMailer/PHPMailer/security/advisories/GHSA-5f37-gxvh-23v6"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2016-10033"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/42221"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/42024"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/41996"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/41962"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/40986"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/40974"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/40970"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/40969"},{"type":"WEB","url":"https://www.exploit-db.com/exploits/40968"},{"type":"PACKAGE","url":"https://github.com/PHPMailer/PHPMailer"},{"type":"WEB","url":"https://github.com/FriendsOfPHP/security-advisories/blob/master/phpmailer/phpmailer/CVE-2016-10033.yaml"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-24T10:46:19.745768974Z"}}