CVE-2019-11043

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Last Modified: UTC

Critical Critical Impact What does this mean?
8.1 CVSS v3 Base Score

Description

The MITRE CVE dictionary describes this issue as

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.

Statement

This issue only affects instances running php-fpm under nginx server software as environment paths and parameters are handled by different code pieces depending on the server php-fpm is running under. The code where this issue is found is used exclusively when php-fpm detects the request came through an nginx server.

Red Hat Product Security team rated this issue as having a Critical security impact as an attacker may take advantage from the existing bug to cause Remote Code Execution on network exposed software.

Mitigation

1) Check your nginx configuration files, specially the ones related to php-fpm for presence of pattern bellow on fastcgi_split_path_info regex and PATH_INFO parameter:

     fastcgi_split_path_info     ^(.+?\.php)(/.*)$;
     fastcgi_param    PATH_INFO  $fastcgi_path_info;

2) If fastcgi_split_path_info regex matches with the one above, for each fastcgi_param PATH_INFO entry perform the following change:

     fastcgi_param    PATH_INFO  $fastcgi_path_info if_not_empty;

This step will allow you to safely continue using PATH_INFO parameter while the patch is not applied.

3) Restart your nginx instance:

     systemctl restart nginx

Additional Information

External References

Content from www.cve.org is not included.https://www.cve.org/CVERecord?id=CVE-2019-11043

Content from nvd.nist.gov is not included.https://nvd.nist.gov/vuln/detail/CVE-2019-11043

Content from www.nginx.com is not included.https://www.nginx.com/blog/php-fpm-cve-2019-11043-vulnerability-nginx/

Content from www.cisa.gov is not included.https://www.cisa.gov/known-exploited-vulnerabilities-catalog

Affected Packages and Issued Red Hat Security Errata

Products / Services Components State Errata
Red Hat Enterprise Linux 5 php Not affected
Red Hat Enterprise Linux 5 php53 Not affected
Red Hat Enterprise Linux 6 php Fixed RHSA-2019:3287
Red Hat Enterprise Linux 7 php Fixed RHSA-2019:3286
Red Hat Enterprise Linux 7.6 Extended Update Support php Fixed RHSA-2020:2835
Red Hat Enterprise Linux 8 php:7.2 Fixed RHSA-2019:3735
Red Hat Enterprise Linux 8 php:7.3 Fixed RHSA-2019:3736
Red Hat Enterprise Linux 8.0 Update Services for SAP Solutions php:7.2 Fixed RHSA-2020:0322
Red Hat Software Collections rh-php73-php Not affected
Red Hat Software Collections for Red Hat Enterprise Linux 6 rh-php70-php Fixed RHSA-2019:3724
Unless explicitly stated as not affected, all previous versions of packages in any minor update stream of a product listed here should be assumed vulnerable, although may not have been subject to full analysis.

Common Vulnerability Scoring System (CVSS) Score Details

Important note

CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authorities (CNA) source for its products and services (see Red Hat classifications ).

CVSS v3 Score Breakdown Red Hat NVD
CVSS v3 Base Score 8.1 9.8
Attack Vector Network Network
Attack Complexity High Low
Privileges Required None None
User Interaction None None
Scope Unchanged Unchanged
Confidentiality Impact High High
Integrity Impact High High
Availability Impact High High

CVSS v3 Vector

Red Hat CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

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

Frequently Asked Questions

Why is Red Hat's CVSS v3 score or Impact different from other vendors?

 For open source software shipped by multiple vendors, the CVSS base scores may vary for each vendor's version depending on the version they ship, how they ship it, the platform, and even how the software is compiled. This makes scoring of vulnerabilities difficult for third-party vulnerability databases such as NVD that only provide a single CVSS base score for each vulnerability. Red Hat scores reflect how a vulnerability affects our products specifically.

For more information, see https://access.redhat.com/solutions/762393.

My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
  • "Under investigation" doesn't necessarily mean that the product is affected by this vulnerability. It only means that our Analysis Team is still working on determining whether the product is affected and how it is affected.
  • "Affected" means that our Analysis Team has determined that this product is affected by this vulnerability and might release a fix to address this in the near future.

What can I do if my product is listed as "Will not fix"?

 A "will not fix" status means that a fix for an affected product version is not planned or not possible due to complexity, which may create additional risk.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Upgrade to a supported product version that includes a fix for this vulnerability (recommended).
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.

What can I do if my product is listed as "Fix deferred"?

 A deferred status means that a fix for an affected product version is not guaranteed due to higher-priority development work.

Available options depend mostly on the Impact of the vulnerability and the current Life Cycle phase of your product. Overall, you have the following options:
  • Apply a mitigation (if one exists).
  • Open a This content is not included.support case to request a prioritization of releasing a fix for this vulnerability.
  • Red Hat Engineering focuses on addressing high-priority issues based on their complexity or limited lifecycle support. Therefore, lower-priority issues will not receive immediate fixes.

What is a mitigation?

 A mitigation is an action that can be taken to reduce the impact of a security vulnerability, without deploying any fixes.

I have a Red Hat product but it is not in the above list, is it affected?

 The listed products were found to include one or more of the components that this vulnerability affects. These products underwent a thorough evaluation to determine their affectedness by this vulnerability. Note that layered products (such as container-based offerings) that consume affected components from any of the products listed in this table may be affected and are not represented.

Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?

 In order to maintain code stability and compatibility, Red Hat usually does not rebase packages to entirely new versions. Instead, we backport fixes and new features to an older version of the package we distribute. This can result in some security scanners that only consider the package version to report the package as vulnerable. To avoid this, we suggest that you use an approved vulnerability scanner from our This content is not included.Red Hat Vulnerability Scanner Certification program.