Description
Apache HTTP Server, in all releases prior to 2.2.32 and 2.4.25, was liberal in the whitespace accepted from requests and sent in response lines and headers. Accepting these different behaviors represented a security concern when httpd participates in any chain of proxies or interacts with back-end application servers, either through mod_proxy or using conventional CGI mechanisms, and may result in request smuggling, response splitting and cache pollution.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.2.0 to 2.2.31, 2.4.1 to 2.4.23 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | apache2 | 2.4.25-1 | — |
| Debian 13 | apache2 | 2.4.25-1 | — |
| Debian 12 | apache2 | 2.4.25-1 | — |
| Debian 8 | apache2 | 2.4.10-10+deb8u8 | DSA-3796-1 |
| Debian 7 | apache2 | 2.2.22-13+deb7u8 | DLA-841-2, DLA-841-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | apache2 | 2.4.18-2ubuntu3.2 | USN-3279-1 |
| Ubuntu 14.04 LTS | apache2 | 2.4.7-1ubuntu4.15 | USN-3279-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 7 | httpd +5 | 2.4.6-45.el7_3.4 | RHSA-2017:0906 |
| RHEL 7 | mod_ssl +1 | 1:2.4.6-45.el7_3.4 | RHSA-2017:0906 |
| RHEL 6 | httpd +3 | 2.2.15-60.el6_9.4 | RHSA-2017:1721 |
| RHEL 6 | mod_ssl | 1:2.2.15-60.el6_9.4 | RHSA-2017:1721 |
| RHEL 2 | httpd24-httpd +5 | 2.4.25-9.el6 | RHSA-2017:1161 |
| RHEL 2 | httpd24-mod_ssl +1 | 1:2.4.25-9.el6 | RHSA-2017:1161 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +7 | 2.4.23-120.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_security | 2.9.1-19.GA.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.23-120.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.0.2h-13.jbcs.el6 | RHSA-2017:1414, RHSA-2017:1413 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP3 | apache2 | 2.4.23-29.24.1 | SUSE-SU-2018:2815-1 |
| SLES 12 SP2 | apache2 | 2.4.23-21.1 | SUSE-SU-2018:2815-2, SUSE-SU-2018:2815-1, SUSE-SU-2017:0797-1 |
| SLES 12 SP1 | apache2 | 2.4.16-19.1 | SUSE-SU-2018:2554-1, SUSE-SU-2017:0801-1 |
| SLES 11 SP4 | apache2 | 2.2.12-69.1 | SUSE-SU-2017:0729-1 |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Studio Onsite 1.3 | apache2 | 2.2.12-69.1 | SUSE-SU-2017:0729-1 |
| SLES for SAP 12 SP3 | apache2 | 2.4.23-29.24.1 | SUSE-SU-2018:2815-1 |
| SLES for SAP 12 SP2 | apache2 | 2.4.23-21.1 | SUSE-SU-2018:2815-1, SUSE-SU-2017:0797-1 |
| SLES for SAP 12 SP1 | apache2 | 2.4.16-19.1 | SUSE-SU-2018:2554-1, SUSE-SU-2017:0801-1 |
| SLES for SAP 11 SP4 | apache2 | 2.2.12-69.1 | SUSE-SU-2017:0729-1 |
| SUSE OpenStack Cloud 7 | apache2 | 2.4.23-29.24.1 | SUSE-SU-2018:2815-1 |
| SUSE Enterprise Storage 4 | apache2 | 2.4.23-29.24.1 | SUSE-SU-2018:2815-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 7 | httpd +5 | 2.4.6-45.0.1.el7_3.4 | ELSA-2017-0906 |
| Oracle Linux 7 | mod_ssl +1 | 1:2.4.6-45.0.1.el7_3.4 | ELSA-2017-0906 |
Advisories 17
- RHSA-2017:1721 Red Hat Security Advisory: httpd security and bug fix update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:1414 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.23 Service Pack 1 for RHEL 6 Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:1413 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.23 Service Pack 1 for RHEL 7 Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:1161 Red Hat Security Advisory: httpd24-httpd security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2017:0906 Red Hat Security Advisory: httpd security and bug fix update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- USN-3279-1 apache2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-841-1 apache2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-841-2 apache2 - regression update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3796-1 apache2 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2018:2815-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0801-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0797-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2017:0729-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:2815-2 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2018:2554-1 Security update for apache2 SUSE / openSUSE Security Updates · May 2, 2025
- WID-SEC-2025-0370 Apple Mac OS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Feb 13, 2025
- ELSA-2017-0906 Moderate: httpd security and bug fix update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Apr 12, 2017
References
- https://support.apple.com/HT208221
- DSA-3796 vendor-advisory
- RHSA-2017:1721 vendor-advisory
- 1037508 vdb-entry
- RHSA-2017:1413 vendor-advisory
- RHSA-2017:1161 vendor-advisory
- https://www.tenable.com/security/tns-2017-04
- RHSA-2017:1414 vendor-advisory
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbmu03753en_us
- 95077 vdb-entry
- https://h20566.www2.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03725en_us
- RHSA-2017:1415 vendor-advisory
- RHSA-2017:0906 vendor-advisory
- https://httpd.apache.org/security/vulnerabilities_24.html#CVE-2016-8743
- GLSA-201701-36 vendor-advisory
- https://security.netapp.com/advisory/ntap-20180423-0001/
- [httpd-cvs] 20190815 svn commit: r1048743 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20190815 svn commit: r1048742 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20190815 svn commit: r1048743 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20190815 svn commit: r1048742 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058586 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058586 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058587 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20200401 svn commit: r1058587 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/vulnerabilities-httpd.xml security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilit mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073140 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.ht mailing-list
- [httpd-cvs] 20210330 svn commit: r1073140 [4/4] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabilities_24.ht mailing-list
- [httpd-cvs] 20210330 svn commit: r1888194 [10/13] - /httpd/site/trunk/content/security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073139 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073146 [2/3] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities-httpd.xml security/vulnerabilities_22.html security/vulnerabilities_24.html mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073149 [11/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073146 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/cvejsontohtml.py security/vulnerabilities-httpd.xml security/vulnerabilities_22.html security/vulnerabilities_24.html mailing-list
- [httpd-cvs] 20210330 svn commit: r1888217 - /httpd/site/trunk/content/security/json/CVE-2016-8743.json mailing-list
- [httpd-cvs] 20210330 svn commit: r1073163 - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2016-8743.json security/vulnerabilities_22.html security/vulnerabilities_24.html mailing-list
- [httpd-cvs] 20210330 svn commit: r1888221 - /httpd/site/trunk/content/security/json/CVE-2016-8743.json mailing-list
- [httpd-cvs] 20210330 svn commit: r1073161 - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2016-8743.json security/vulnerabilities_22.html security/vulnerabilities_24.html mailing-list
- [httpd-cvs] 20210603 svn commit: r1075360 [2/3] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list
- [httpd-cvs] 20210606 svn commit: r1075467 [2/2] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2021-31618.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list
- [httpd-cvs] 20210606 svn commit: r1075470 [3/4] - in /websites/staging/httpd/trunk/content: ./ security/json/CVE-2020-13938.json security/vulnerabilities_13.html security/vulnerabilities_20.html security/vulnerabilities_22.html security/vulnerabiliti mailing-list