Vulnerability in Joomla Joomla\!
CVE-2016-10033
The mailSend function in the 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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.997 (100.0th percentile), scored .
Very high probability of exploitation in the next 30 days — among the top 0.1% most-likely-to-be-exploited CVEs. 100th percentile — 100.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
The 30-day trend appears once there are two daily scores.
Affected products
Weakness classification (CWE)
CISA KEV (Known Exploited Vulnerabilities)
This CVE is on the CISA KEV catalog, added on . CISA KEV inclusion means CISA has confirmed in-the-wild exploitation; US federal agencies are required to remediate within a published due date.
BOD 22-01 due date: .
Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Public proof-of-concept exploits
References
- packetstormsecurity.com/files/140350/PHPMailer-Sendmail-Argument-Injection.html (Exploit, VDB Entry, Third Party Advisory)
- www.drupal.org/psa-2016-004 (Third Party Advisory)
- www.exploit-db.com/exploits/42221/ (Exploit, VDB Entry, Third Party Advisory, exploit)
- www.exploit-db.com/exploits/40969/ (Exploit, VDB Entry, Third Party Advisory, exploit)
- www.exploit-db.com/exploits/41962/ (Exploit, VDB Entry, Third Party Advisory, exploit)
- www.exploit-db.com/exploits/40968/ (Exploit, Patch, VDB Entry, Third Party Advisory, exploit)
- legalhackers.com/advisories/PHPMailer-Exploit-Remote-Code-Exec-CVE-2016-10033-V… (Exploit, Patch, Third Party Advisory)
- github.com/PHPMailer/PHPMailer/releases/tag/v5.2.18 (Patch, Vendor Advisory)
- www.securityfocus.com/archive/1/539963/100/0/threaded (mailing-list, VDB Entry, Third Party Advisory, Broken Link)
- github.com/PHPMailer/PHPMailer/wiki/About-the-CVE-2016-10033-and-CVE-2016-10045… (Patch, Vendor Advisory)
Frequently asked questions
- What is CVE-2016-10033?
- CVE-2016-10033 is a critical-severity vulnerability in Joomla Joomla\!, classified under Argument Injection. CVSS score: 9.8/10. Published 2016-12-30.
- How severe is CVE-2016-10033?
- Critical severity. CVSS v3 base score is 9.8 out of 10.
- Is CVE-2016-10033 known to be exploited?
- Yes. CVE-2016-10033 is listed in the CISA Known Exploited Vulnerabilities catalog (added 2025-07-07), indicating it is being actively exploited. 227 public proof-of-concept repositories are indexed.