PHP FastCGI Process Manager (FPM) Buffer Overflow Vulnerability

Exploited · KEV 2022-03-25RansomwareMetasploit moduleCVE-2019-11043CWE-120

Exploited since 2022-03-25. No WAF vendor names it yet. Our CRS test: blocked.

Edge rules

0/8

Our test

Blocked

CVSS

8.7

EPSS

99.8% Top 0.1%

Posts, 14d

Published

2019-10-28

In PHP versions 7.1.x below 7.1.33, 7.2.x below 7.2.24 and 7.3.x below 7.3.11 in certain configurations of FPM setup it is possible to cause FPM module to write past allocated buffers into the space reserved for FCGI protocol data, thus… More

Edge coverage

Claimed by vendors

CloudflareBefore feed historyOlder than its feedWe measured: passed AWSBefore feed historyOlder than its feedWe measured: passed Microsoft AzureNo public claimNot named Google CloudBefore feed historyOlder than its feedWe measured: blocked FastlyBefore feed historyOlder than its feed F5Before feed historyOlder than its feed AkamaiNo public sourceNo public changelog OWASP CRSBefore feed historyOlder than its feed

Ask Vigil

AI · answers from this page

Ask about CVE-2019-11043: who's covered, what to patch first, how vendors compare. I cite sources and won't help with attacks.

Workers AI (Llama 3.3). Can be wrong: check the cited source.

Severity, decoded

CVSS 3.1

8.7High

High · 8.7 / 10

Exploitable over the network under specific conditions, with no privileges and no user interaction, leading to full loss of confidentiality and integrity, and the impact can reach components beyond the vulnerable one.

Over the internetNo login neededNo user actionHard to pull offSpreads beyond the appSerious impact

How the score is built8 metrics

Attack vectorAn attacker can reach it over the internet; no access to your network needed.
Network
Attack complexityThe attack only works when conditions outside the attacker's control line up.
High
Privileges requiredNo account or login is needed.
None
User interactionNo one has to click or open anything; the attack works on its own.
None
ScopeThe attack can spread beyond the vulnerable component to other parts of the system.
Changed
Confidentiality impactAn attacker can read all data the affected component holds, or the most sensitive parts of it.
High
Integrity impactAn attacker can change any data or files the affected component protects.
High
Availability impactThe component keeps working normally.
None

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

CISA's assessmentSSVC, from the CVE record

ExploitationActive

Attackers are exploiting this in the wild.

AutomatableNo

At least one step needs hands-on work, which slows mass attacks.

Technical impactTotal

A successful attack gives full control over the affected software or all of its data.

Public exploits

4 found

1 Metasploit2 Exploit-DB1 Scanner template0 GitHub PoCs

MetasploitPHP-FPM Underflow RCE2019-10-22 · exploit · rank Normal · has check
Exploit-DBPHP-FPM - Underflow Remote Code Execution (Metasploit)2020-03-09 · remote · php · verified
Exploit-DBPHP-FPM + Nginx - Remote Code Execution2019-10-28 · webapps · php
NucleiCVE-2019-11043.yamldetection template, replayed in our lab

Links are to third-party code: never run it outside an isolated lab.

Timeline

2019-10-22
Metasploit module published
PHP-FPM Underflow RCE
2019-10-28
CVE published
CVE List
2019-10-28
Exploit published on Exploit-DB
PHP-FPM + Nginx - Remote Code Execution
2022-03-25
Added to CISA KEV
Confirmed exploitation in the wild
2026-11-02
Our test: OWASP Core Rule Set blocked it
paranoia level 1, anomaly threshold 5, default CRS settings
2026-11-02
Our test: OWASP Core Rule Set blocked it
paranoia level 2, anomaly threshold 5, default CRS settings