NULL pointer dereference in Apache HTTP Server - CVE-2021-26691

Vulnerability identifier: #VU53776

CSH Severity: Low

CVSS v4: 8.2 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-26691

CWE-ID: CWE-476

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to a NULL pointer dereference error in mod_session. A a malicious backend server or SessionHeader can trigger a denial of service (DoS) condition.

Apache HTTP Server
Amazon Linux AMI
Gentoo Linux
SUSE Manager Retail Branch Server
SUSE Manager Proxy
SUSE CaaS Platform
SUSE Manager Server
SUSE Enterprise Storage
Red Hat Enterprise Linux Desktop
Red Hat Enterprise Linux Workstation
Red Hat Enterprise Linux Server
Red Hat Enterprise Linux for IBM z Systems
Red Hat Enterprise Linux for Power, big endian
Red Hat Enterprise Linux for Scientific Computing
Red Hat Enterprise Linux for Power, little endian
Anolis OS
Red Hat Enterprise Linux for ARM 64
SUSE OpenStack Cloud Crowbar
SUSE OpenStack Cloud
HPE Helion Openstack
Red Hat Enterprise Linux for x86_64
Red Hat Enterprise Linux for ARM 64 - Extended Update Support
Red Hat Enterprise Linux Server - AUS
Red Hat Enterprise Linux Server - TUS
Red Hat Enterprise Linux for Power, little endian - Extended Update Support
Red Hat Enterprise Linux for x86_64 - Extended Update Support
Red Hat Enterprise Linux for IBM z Systems - Extended Update Support
SUSE Linux Enterprise Server
SUSE Linux Enterprise Server for SAP
SUSE Linux Enterprise Software Development Kit
Slackware Linux
Ubuntu
SUSE Linux Enterprise High Performance Computing
SUSE Linux Enterprise Module for Basesystem
SUSE Linux Enterprise Module for Server Applications
openEuler
Fedora
MELSOFT iQ AppPortal
jbcs-httpd24-openssl-pkcs11 (Red Hat package)
jbcs-httpd24-openssl-chil (Red Hat package)
jbcs-httpd24-apr-util (Red Hat package)
jbcs-httpd24-apr (Red Hat package)
jbcs-httpd24-mod_http2 (Red Hat package)
jbcs-httpd24-nghttp2 (Red Hat package)
jbcs-httpd24-mod_md (Red Hat package)
apache2 (Debian package)
jbcs-httpd24-httpd (Red Hat package)
jbcs-httpd24-mod_security (Red Hat package)
jbcs-httpd24-curl (Red Hat package)
Red Hat Enterprise Linux Server for x86_64 - Update Services for SAP Solutions
Red Hat Enterprise Linux Server for Power LE - Update Services for SAP Solutions
SUSE Linux Enterprise Module for Packagehub Subpackages
mod_http2
mod_md
mod_ssl
httpd-manual
mod_session
mod_proxy_html
mod_ldap
httpd-tools
httpd-devel
httpd
httpd24 (Red Hat package)
apache2-prefork-debuginfo
apache2-example-pages
apache2-prefork
apache2-debuginfo
apache2-debugsource
apache2-doc
apache2
apache2-utils
apache2-utils-debuginfo
apache2-worker
apache2-worker-debuginfo
apache2-devel
apache2-bin (Ubuntu package)
apache2 (Ubuntu package)
httpd-filesystem
apache2-event
apache2-event-debuginfo
httpd-help
httpd-debuginfo
httpd-debugsource
JBoss Core Services
EasyApache
Dell Secure Connect Gateway
Instantis EnterpriseTrack
Oracle Secure Backup
Watson Studio on Cloud Pak for Data
XtremIO X2
Maximo Application Suite - IoT Component
CTPView
IBM DS8000 Hardware Management Console

Install updates from vendor's website.

Apache HTTP Server - update to 2.4.47
MELSOFT iQ AppPortal - update to 1.29F
jbcs-httpd24-openssl-pkcs11 (Red Hat package) - addressed in versions 0.4.10-22.el8jbcs, 0.4.10-22.jbcs.el7
jbcs-httpd24-openssl-chil (Red Hat package) - addressed in versions 1.0.0-7.el8jbcs, 1.0.0-7.jbcs.el7
jbcs-httpd24-apr-util (Red Hat package) - addressed in versions 1.6.1-84.el8jbcs, 1.6.1-84.jbcs.el7
jbcs-httpd24-apr (Red Hat package) - addressed in versions 1.6.3-107.el8jbcs, 1.6.3-107.jbcs.el7
jbcs-httpd24-mod_http2 (Red Hat package) - addressed in versions 1.15.7-21.el8jbcs, 1.15.7-21.jbcs.el7
jbcs-httpd24-nghttp2 (Red Hat package) - addressed in versions 1.39.2-39.el8jbcs, 1.39.2-39.jbcs.el7
jbcs-httpd24-mod_md (Red Hat package) - addressed in versions 2.0.8-40.el8jbcs, 2.0.8-40.jbcs.el7
apache2 (Debian package) - update to 2.4.38-3+deb10u5
JBoss Core Services - update to 2.4.37 SP10
jbcs-httpd24-httpd (Red Hat package) - addressed in versions 2.4.37-78.el8jbcs, 2.4.37-78.jbcs.el7
jbcs-httpd24-mod_security (Red Hat package) - addressed in versions 2.9.2-67.GA.el8jbcs, 2.9.2-67.GA.jbcs.el7
EasyApache - update to 4 2021-6-2
Dell Secure Connect Gateway - update to 5.12.00.10
jbcs-httpd24-curl (Red Hat package) - addressed in versions 7.78.0-2.el8jbcs, 7.78.0-2.jbcs.el7
Oracle Secure Backup - update to 18.1.0.1.0
mod_http2 - update to 1.15.7-3
mod_md - update to 2.0.8-8
mod_ssl - addressed in versions 2.4.6-97, 2.4.37-43.0.1
httpd-manual - addressed in versions 2.4.6-97, 2.4.37-43.0.1
mod_session - addressed in versions 2.4.6-97, 2.4.37-43.0.1
mod_proxy_html - addressed in versions 2.4.6-97, 2.4.37-43.0.1
mod_ldap - addressed in versions 2.4.6-97, 2.4.37-43.0.1
httpd-tools - addressed in versions 2.4.6-97, 2.4.37-43.0.1
httpd-devel - addressed in versions 2.4.6-97, 2.4.37-43.0.1
httpd - addressed in versions 2.4.6-97, 2.4.37-43.0.1
httpd24 (Red Hat package) - update to 2.4.6-97.el7_9.4
apache2-prefork-debuginfo - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-example-pages - update to 2.4.23-29.74.1
apache2-prefork - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-debuginfo - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-debugsource - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-doc - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2 - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-utils - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-utils-debuginfo - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-worker - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-worker-debuginfo - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-devel - addressed in versions 2.4.23-29.74.1, 2.4.33-3.50.1, 2.4.43-3.22.1
apache2-bin (Ubuntu package) - addressed in versions 2.4.29-1ubuntu4.16, 2.4.41-4ubuntu3.3, 2.4.46-1ubuntu1.2, 2.4.46-4ubuntu1.1, 2.4.182ubuntu3.17+esm1
apache2 (Ubuntu package) - addressed in versions 2.4.29-1ubuntu4.16, 2.4.41-4ubuntu3.3, 2.4.46-1ubuntu1.2, 2.4.46-4ubuntu1.1, 2.4.182ubuntu3.17+esm1
httpd-filesystem - update to 2.4.37-43.0.1
apache2-event - update to 2.4.43-3.22.1
apache2-event-debuginfo - update to 2.4.43-3.22.1
httpd-tools - update to 2.4.43-7
httpd-filesystem - update to 2.4.43-7
httpd-help - update to 2.4.43-7
mod_proxy_html - update to 2.4.43-7
mod_session - update to 2.4.43-7
mod_ldap - update to 2.4.43-7
httpd-debuginfo - update to 2.4.43-7
httpd-debugsource - update to 2.4.43-7
httpd-devel - update to 2.4.43-7
mod_md - update to 2.4.43-7
mod_ssl - update to 2.4.43-7
httpd - update to 2.4.43-7
httpd - addressed in versions 2.4.49-1.fc34, 2.4.49-1.fc35
Watson Studio on Cloud Pak for Data - addressed in versions 4.8.7, 5.1.0
XtremIO X2 - update to 6.4.1-11
Maximo Application Suite - IoT Component - addressed in versions 8.7.20, 8.8.16, 9.0.6
CTPView - update to 9.1R5
IBM DS8000 Hardware Management Console - update to 89.30.68.0

• https://downloads.apache.org/httpd/CHANGES_2.4.48

• Multiple vulnerabilities in Apache HTTP Server
• cPanel update for EasyApache
• Slackware Linux update for httpd
• Debian update for apache2
• Amazon Linux AMI update for httpd24
• Gentoo update for Apache
• Red Hat Enterprise Linux 8 update for the httpd:2.4 module
• Multiple vulnerabilities in Red Hat JBoss Core Services Apache HTTP Server
• Red Hat Enterprise Linux 7 update for httpd
• Multiple vulnerabilities in Oracle Secure Backup
• Multiple vulnerabilities in Mitsubishi Electric MELSOFT iQ AppPortal
• Multiple vulnerabilities in IBM DS8000 Hardware Management Console
• SUSE update for apache2
• SUSE update for apache2
• SUSE update for apache2
• Ubuntu update for apache2
• Ubuntu update for apache2
• Multiple vulnerabilities in DELL Secure Connect Gateway Security
• Multiple vulnerabilities in Instantis EnterpriseTrack
• Multiple vulnerabilities in Dell XtremIO X2
• Multiple vulnerabilities in Juniper Networks CTPView
• openEuler 20.03 LTS SP1 update for httpd
• Red Hat Enterprise Linux 8 update for the httpd:2.4 module
• Fedora 34 update for httpd
• Fedora 35 update for httpd
• Multiple vulnerabilities in IBM Watson Studio on Cloud Pak for Data
• Multiple vulnerabilities in IBM Maximo Application Suite - IoT Component
• Anolis OS update for httpd
• Anolis OS update for httpd:2.4 module