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CVE-2019-11043

Underflow in PHP-FPM can lead to RCE

  • High 8.7
  • Exploited: added to CISA KEV 25 Mar 2022
  • Used in ransomware campaigns

Description

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 opening the possibility of remote code execution.

Key facts

Published
28 Oct 2019
Last changed
21 Oct 2025
Assigned by
php
KEV added
25 Mar 2022
KEV fix due
15 Apr 2022
Used in ransomware
Yes, according to CISA
EPSS
99.783% likely to be exploited in the next 30 days, higher than 99.956% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: no; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 8.7CVSS 3.1, Highfrom the CNA (php)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N

What to do

  • Configuring nginx (or other server that implements the front-end part of the FPM protocol) to check for the existence of the target file before passing it to PHP FPM (e.g. "try_files $uri =404" or "if (-f $uri)" in nginx) for would prevent this vulnerability from happening.CNA workaround statement
  • Apply updates per vendor instructions.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
PHPPHP
  • 7.1.x up to but excluding 7.1.33 (affected)
  • 7.2.x up to but excluding 7.2.24 (affected)
  • 7.3.x up to but excluding 7.3.11 (affected)

Timeline

  1. 28 Oct 2019 Published
  2. 25 Mar 2022 CVE-2019-11043 added to CISA KEV
  3. 25 Mar 2022 Added to the CISA KEV catalogue

Weakness

References