critical Known exploitedREV. 01

CVE-2016-10033PHPMailer — Command Injection Through the Sender Address

A widely used mail library passes the sender address into the system mail command without cleaning it, so a contact form can hand an attacker code execution on the web server.

YOUR NEXT MOVE

Upgrade the mail library past 5.2.18, and validate sender addresses before they reach it.

Read the risk

THE VITAL STATS
CVSS score
9.8/ 10
CVSS v3.1
EPSS probability
100%
Likelihood of exploitation
Attack complexity
Low
Conditions needed to exploit
Known exploited
Yes — CISA KEV
CVE published
2016-12-30
Added to KEV
2025-07-07
Exploit published
Yes
Confidence
medium
Kill chain
initial access
MITRE ATT&CK
T1190
Severity
critical

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attacker needsA form that passes a user-supplied sender address to the library

Fixed inPHPMailer 5.2.18

Behind the card

5 REFERENCES
Field-level provenanceTRACE THE SOURCES +

Which source supports each field, when it was retrieved, and who extracted it.

FieldsSourceRetrievedExtractorConfidence
cvss, exploitation.attack_complexity, exploitation.exploit_available, references, published_atnvd.nist.gov2026-08-07scrty-crds-pipeline/0.1high
exploitation.known_exploited, exploitation.kev_addedcisa.gov2026-08-07scrty-crds-pipeline/0.1high
epssapi.first.org2026-08-07scrty-crds-pipeline/0.1high
title, summary, severity, remediation, mitre_attack, kill_chain, recommended_action, confidence, tags, exploitation.prerequisitesnvd.nist.gov2026-08-07claude-codehigh

Printing history

THE RECORD
  1. r1Initial base card

First printing. This card has not been reprinted since publication.

crds:cve-2016-10033 · CRDS 0.1 · Issued 2026-08-07