CVE-2020-11993: High severity Apache HTTP Server vulnerability

Published Aug 5, 2020
·
Updated

A flaw was found in Apache httpd in versions 2.4.20 to 2.4.43. Logging using the wrong pool by modhttp2 at debug/trace log level may lead to potential crashes and denial of service. The highest threat from this vulnerability is to system availability.

Other sources

A flaw was found in httpd before version 2.4.46. Logging using the wrong pool by modhttp2 at debug/trace log level may lead to potential crashes and denial of service.

Upstream patch:

https://github.com/icing/modh2/commit/89773a4f98ee9a9fb402470e04b6f4044faa7fdf

— Red Hat

Apache HTTP Server versions 2.4.20 to 2.4.43 When trace/debug was enabled for the HTTP/2 module and on certain traffic edge patterns, logging statements were made on the wrong connection, causing concurrent use of memory pools. Configuring the LogLevel of modhttp2 above "info" will mitigate this vulnerability for unpatched servers.

Affected Software

40 affected componentsFixes available
redhat/jbcs-httpd24-apr<0:1.6.3-104.jbcs.el6
0:1.6.3-104.jbcs.el6
redhat/jbcs-httpd24-apr-util<0:1.6.1-75.jbcs.el6
0:1.6.1-75.jbcs.el6
redhat/jbcs-httpd24-brotli<0:1.0.6-38.jbcs.el6
0:1.0.6-38.jbcs.el6
redhat/jbcs-httpd24-curl<0:7.64.1-44.jbcs.el6
0:7.64.1-44.jbcs.el6
redhat/jbcs-httpd24-httpd<0:2.4.37-64.jbcs.el6
0:2.4.37-64.jbcs.el6
redhat/jbcs-httpd24-jansson<0:2.11-53.jbcs.el6
0:2.11-53.jbcs.el6
redhat/jbcs-httpd24-nghttp2<0:1.39.2-34.jbcs.el6
0:1.39.2-34.jbcs.el6
redhat/jbcs-httpd24-openssl<1:1.1.1c-32.jbcs.el6
1:1.1.1c-32.jbcs.el6
redhat/jbcs-httpd24-apr<0:1.6.3-104.jbcs.el7
0:1.6.3-104.jbcs.el7
redhat/jbcs-httpd24-apr-util<0:1.6.1-75.jbcs.el7
0:1.6.1-75.jbcs.el7
redhat/jbcs-httpd24-brotli<0:1.0.6-38.jbcs.el7
0:1.0.6-38.jbcs.el7
redhat/jbcs-httpd24-curl<0:7.64.1-44.jbcs.el7
0:7.64.1-44.jbcs.el7
redhat/jbcs-httpd24-httpd<0:2.4.37-64.jbcs.el7
0:2.4.37-64.jbcs.el7
redhat/jbcs-httpd24-jansson<0:2.11-53.jbcs.el7
0:2.11-53.jbcs.el7
redhat/jbcs-httpd24-nghttp2<0:1.39.2-34.jbcs.el7
0:1.39.2-34.jbcs.el7
redhat/jbcs-httpd24-openssl<1:1.1.1c-32.jbcs.el7
1:1.1.1c-32.jbcs.el7
redhat/jbcs-httpd24-openssl-chil<0:1.0.0-1.jbcs.el7
0:1.0.0-1.jbcs.el7
redhat/httpd24-httpd<0:2.4.34-22.el7
0:2.4.34-22.el7
Apache HTTP Server>=2.4.20<=2.4.43
NetApp Clustered Data ONTAP
Canonical Ubuntu Linux=16.04
Canonical Ubuntu Linux=18.04
Canonical Ubuntu Linux=20.04
openSUSE Leap=15.1
openSUSE Leap=15.2
Debian Debian Linux=10.0
Fedoraproject Fedora=31
Fedoraproject Fedora=32
Oracle Communications Element Manager>=8.2.0<=8.2.2
Oracle Communications Session Report Manager>=8.2.0<=8.2.2
Oracle Communications Session Route Manager>=8.2.0<=8.2.2
Oracle Enterprise Manager Ops Center=12.4.0.0
Oracle Hyperion Infrastructure Technology=11.1.2.4
Oracle Instantis Enterprisetrack=17.1
Oracle Instantis Enterprisetrack=17.2
Oracle Instantis Enterprisetrack=17.3
Oracle ZFS Storage Appliance Kit=8.8
Apache HTTP Server>=2.4.20<2.4.44
redhat/httpd<2.4.44
2.4.44
debian/apache2
2.4.62-1~deb11u12.4.67-1~deb11u32.4.68-1~deb12u12.4.67-1~deb12u32.4.68-1~deb13u12.4.67-1~deb13u32.4.68-1

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade redhat/jbcs-httpd24-apr to a version that resolves this vulnerability.

    Fixed in 0:1.6.3-104.jbcs.el6
  2. Upgrade

    Upgrade redhat/jbcs-httpd24-apr-util to a version that resolves this vulnerability.

    Fixed in 0:1.6.1-75.jbcs.el6
  3. Upgrade

    Upgrade redhat/jbcs-httpd24-brotli to a version that resolves this vulnerability.

    Fixed in 0:1.0.6-38.jbcs.el6
  4. Upgrade

    Upgrade redhat/jbcs-httpd24-curl to a version that resolves this vulnerability.

    Fixed in 0:7.64.1-44.jbcs.el6
  5. Upgrade

    Upgrade redhat/jbcs-httpd24-httpd to a version that resolves this vulnerability.

    Fixed in 0:2.4.37-64.jbcs.el6
  6. Upgrade

    Upgrade redhat/jbcs-httpd24-jansson to a version that resolves this vulnerability.

    Fixed in 0:2.11-53.jbcs.el6
  7. Upgrade

    Upgrade redhat/jbcs-httpd24-nghttp2 to a version that resolves this vulnerability.

    Fixed in 0:1.39.2-34.jbcs.el6
  8. Upgrade

    Upgrade redhat/jbcs-httpd24-openssl to a version that resolves this vulnerability.

    Fixed in 1:1.1.1c-32.jbcs.el6
  9. Upgrade

    Upgrade redhat/jbcs-httpd24-apr to a version that resolves this vulnerability.

    Fixed in 0:1.6.3-104.jbcs.el7
  10. Upgrade

    Upgrade redhat/jbcs-httpd24-apr-util to a version that resolves this vulnerability.

    Fixed in 0:1.6.1-75.jbcs.el7
  11. Upgrade

    Upgrade redhat/jbcs-httpd24-brotli to a version that resolves this vulnerability.

    Fixed in 0:1.0.6-38.jbcs.el7
  12. Upgrade

    Upgrade redhat/jbcs-httpd24-curl to a version that resolves this vulnerability.

    Fixed in 0:7.64.1-44.jbcs.el7
  13. Upgrade

    Upgrade redhat/jbcs-httpd24-httpd to a version that resolves this vulnerability.

    Fixed in 0:2.4.37-64.jbcs.el7
  14. Upgrade

    Upgrade redhat/jbcs-httpd24-jansson to a version that resolves this vulnerability.

    Fixed in 0:2.11-53.jbcs.el7
  15. Upgrade

    Upgrade redhat/jbcs-httpd24-nghttp2 to a version that resolves this vulnerability.

    Fixed in 0:1.39.2-34.jbcs.el7
  16. Upgrade

    Upgrade redhat/jbcs-httpd24-openssl to a version that resolves this vulnerability.

    Fixed in 1:1.1.1c-32.jbcs.el7
  17. Upgrade

    Upgrade redhat/jbcs-httpd24-openssl-chil to a version that resolves this vulnerability.

    Fixed in 0:1.0.0-1.jbcs.el7
  18. Upgrade

    Upgrade redhat/httpd24-httpd to a version that resolves this vulnerability.

    Fixed in 0:2.4.34-22.el7
  19. Upgrade

    Upgrade redhat/httpd to a version that resolves this vulnerability.

    Fixed in 2.4.44
  20. Upgrade

    Upgrade debian/apache2 to a version that resolves this vulnerability.

    Fixed in 2.4.62-1~deb11u1Fixed in 2.4.67-1~deb11u3Fixed in 2.4.68-1~deb12u1Fixed in 2.4.67-1~deb12u3Fixed in 2.4.68-1~deb13u1Fixed in 2.4.67-1~deb13u3Fixed in 2.4.68-1
  21. Configuration

    For unpatched Apache httpd, configure the LogLevel of mod_http2 to be at "info" or lower (mitigates when debug/trace is enabled for the HTTP/2 module).

    Apache httpd (mod_http2) LogLevel = info (set to "info" or lower; do not set above "info")

Event History

Aug 5, 2020
Data Sourced
via Red Hat·10:13 PM
DescriptionSeverityAffected Software
Aug 7, 2020
CVE Published
12:00 AM
CVE Published
via MITRE·03:32 PM
Data Sourced
via MITRE·03:32 PM
DescriptionWeakness
Data Sourced
via NVD·04:15 PM
RemedyDescriptionSeverityWeaknessAffected Software
Feb 23, 2026
Data Sourced
via Ubuntu·06:47 PM
RemedyDescriptionSeverityAffected Software
Data Sourced
via Launchpad·06:48 PM
Description
Jul 16, 2026
Data Sourced
via Debian·11:38 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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Frequently Asked Questions

1

What is the vulnerability ID?

The vulnerability ID is CVE-2020-11993.

2

What is the severity of CVE-2020-11993?

The severity of CVE-2020-11993 is high.

3

Which versions of Apache HTTP Server are affected by CVE-2020-11993?

Apache HTTP Server versions 2.4.20 to 2.4.43 are affected by CVE-2020-11993.

4

How can I mitigate the vulnerability?

Configuring the LogLevel of mod_http2 above "info" will mitigate CVE-2020-11993.

5

Where can I find more information about CVE-2020-11993?

You can find more information about CVE-2020-11993 at the following references: [1] [2] [3]

Company

Resources

Contact

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