mod_userdir CRLF injection
Priority MEDIUM 46CWE-93Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- Required
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- Low · Low · None
- Fix status
- Partial Red Hat: 9 fixed, 6 without a fix
Attack profile from CVSS 3.0 · NVD. Fix status from CNA and Red Hat.
Summary
Possible CRLF injection allowing HTTP response splitting attacks for sites which use mod_userdir. This issue was mitigated by changes made in 2.4.25 and 2.2.32 which prohibit CR or LF injection into the "Location" or other outbound header key or value. Fixed in Apache HTTP Server 2.4.25 (Affected 2.4.1-2.4.23). Fixed in Apache HTTP Server 2.2.32 (Affected 2.2.0-2.2.31).
Why it matters now
EPSS 0.19882 97th percentileScored 2026-11-07
Fix Partial Red Hat: 4 advisoriesRed Hat: 9 fixed, 6 without a fix
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| Apache | Apache HTTP Server | Fixed in Apache HTTP Server 2.4.25 (Affected 2.4.1-2.4.23); Fixed in Apache HTTP Server 2.2.32 (Affected 2.2.0-2.2.31) | — | No fix listed | CNA |
- Apache HTTP Server VendorApache Affected Fixed in Apache HTTP Server 2.4.25 (Affected 2.4.1-2.4.23); Fixed in Apache HTTP Server 2.2.32 (Affected 2.2.0-2.2.31) Fixed in — No fix listed CNA
CPE configurations NVD · 41
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:apache:http_server:2.2.0:*:*:*:*:*:*:* | 2.2.0 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.2:*:*:*:*:*:*:* | 2.2.2 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.3:*:*:*:*:*:*:* | 2.2.3 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.4:*:*:*:*:*:*:* | 2.2.4 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.6:*:*:*:*:*:*:* | 2.2.6 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.8:*:*:*:*:*:*:* | 2.2.8 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.9:*:*:*:*:*:*:* | 2.2.9 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.10:*:*:*:*:*:*:* | 2.2.10 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.11:*:*:*:*:*:*:* | 2.2.11 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.12:*:*:*:*:*:*:* | 2.2.12 | Vulnerable | Apache |
- cpe:2.3:a:apache:http_server:2.2.0:*:*:*:*:*:*:* Versions 2.2.0 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.2:*:*:*:*:*:*:* Versions 2.2.2 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.3:*:*:*:*:*:*:* Versions 2.2.3 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.4:*:*:*:*:*:*:* Versions 2.2.4 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.6:*:*:*:*:*:*:* Versions 2.2.6 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.8:*:*:*:*:*:*:* Versions 2.2.8 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.9:*:*:*:*:*:*:* Versions 2.2.9 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.10:*:*:*:*:*:*:* Versions 2.2.10 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.11:*:*:*:*:*:*:* Versions 2.2.11 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.12:*:*:*:*:*:*:* Versions 2.2.12 Vulnerable ·Apache
Show 31 more CPE
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:apache:http_server:2.2.13:*:*:*:*:*:*:* | 2.2.13 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.14:*:*:*:*:*:*:* | 2.2.14 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.15:*:*:*:*:*:*:* | 2.2.15 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.16:*:*:*:*:*:*:* | 2.2.16 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.17:*:*:*:*:*:*:* | 2.2.17 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.18:*:*:*:*:*:*:* | 2.2.18 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.19:*:*:*:*:*:*:* | 2.2.19 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.20:*:*:*:*:*:*:* | 2.2.20 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.21:*:*:*:*:*:*:* | 2.2.21 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.22:*:*:*:*:*:*:* | 2.2.22 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.23:*:*:*:*:*:*:* | 2.2.23 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.24:*:*:*:*:*:*:* | 2.2.24 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.25:*:*:*:*:*:*:* | 2.2.25 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.26:*:*:*:*:*:*:* | 2.2.26 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.27:*:*:*:*:*:*:* | 2.2.27 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.29:*:*:*:*:*:*:* | 2.2.29 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.2.31:*:*:*:*:*:*:* | 2.2.31 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.1:*:*:*:*:*:*:* | 2.4.1 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.2:*:*:*:*:*:*:* | 2.4.2 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.3:*:*:*:*:*:*:* | 2.4.3 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.4:*:*:*:*:*:*:* | 2.4.4 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.6:*:*:*:*:*:*:* | 2.4.6 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.7:*:*:*:*:*:*:* | 2.4.7 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.9:*:*:*:*:*:*:* | 2.4.9 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.10:*:*:*:*:*:*:* | 2.4.10 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.12:*:*:*:*:*:*:* | 2.4.12 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.16:*:*:*:*:*:*:* | 2.4.16 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.17:*:*:*:*:*:*:* | 2.4.17 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.18:*:*:*:*:*:*:* | 2.4.18 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.20:*:*:*:*:*:*:* | 2.4.20 | Vulnerable | Apache |
| cpe:2.3:a:apache:http_server:2.4.23:*:*:*:*:*:*:* | 2.4.23 | Vulnerable | Apache |
- cpe:2.3:a:apache:http_server:2.2.13:*:*:*:*:*:*:* Versions 2.2.13 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.14:*:*:*:*:*:*:* Versions 2.2.14 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.15:*:*:*:*:*:*:* Versions 2.2.15 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.16:*:*:*:*:*:*:* Versions 2.2.16 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.17:*:*:*:*:*:*:* Versions 2.2.17 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.18:*:*:*:*:*:*:* Versions 2.2.18 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.19:*:*:*:*:*:*:* Versions 2.2.19 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.20:*:*:*:*:*:*:* Versions 2.2.20 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.21:*:*:*:*:*:*:* Versions 2.2.21 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.22:*:*:*:*:*:*:* Versions 2.2.22 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.23:*:*:*:*:*:*:* Versions 2.2.23 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.24:*:*:*:*:*:*:* Versions 2.2.24 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.25:*:*:*:*:*:*:* Versions 2.2.25 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.26:*:*:*:*:*:*:* Versions 2.2.26 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.27:*:*:*:*:*:*:* Versions 2.2.27 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.29:*:*:*:*:*:*:* Versions 2.2.29 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.2.31:*:*:*:*:*:*:* Versions 2.2.31 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.1:*:*:*:*:*:*:* Versions 2.4.1 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.2:*:*:*:*:*:*:* Versions 2.4.2 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.3:*:*:*:*:*:*:* Versions 2.4.3 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.4:*:*:*:*:*:*:* Versions 2.4.4 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.6:*:*:*:*:*:*:* Versions 2.4.6 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.7:*:*:*:*:*:*:* Versions 2.4.7 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.9:*:*:*:*:*:*:* Versions 2.4.9 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.10:*:*:*:*:*:*:* Versions 2.4.10 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.12:*:*:*:*:*:*:* Versions 2.4.12 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.16:*:*:*:*:*:*:* Versions 2.4.16 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.17:*:*:*:*:*:*:* Versions 2.4.17 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.18:*:*:*:*:*:*:* Versions 2.4.18 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.20:*:*:*:*:*:*:* Versions 2.4.20 Vulnerable ·Apache
- cpe:2.3:a:apache:http_server:2.4.23:*:*:*:*:*:*:* Versions 2.4.23 Vulnerable ·Apache
Remediation
Red Hat 4 advisories
- RHSA-2018:2486 Released 2018-08-16 · Red Hat rating ImportantRed Hat JBoss Core Services Apache HTTP Server 2.4.29 security update
- Red Hat JBoss Core Services
- RHSA-2018:2186 Released 2018-07-12 · Red Hat rating ModerateRed Hat JBoss Core Services Apache HTTP Server 2.4.29 RHEL 6 security update
- Red Hat JBoss Core Services on RHEL 6 Server jbcs-httpd24-apache-commons-daemon-1.1.0-1.redhat_2.1.jbcs.el6, jbcs-httpd24-apache-commons-daemon-jsvc-1:1.1.0-1.redhat_2.jbcs.el6, jbcs-httpd24-apr-1.6.3-14.jbcs.el6 +34
- RHSA-2018:2185 Released 2018-07-12 · Red Hat rating ModerateRed Hat JBoss Core Services Apache HTTP Server 2.4.29 RHEL 7 security update
- Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apache-commons-daemon-1.1.0-1.redhat_2.1.jbcs.el7, jbcs-httpd24-apache-commons-daemon-jsvc-1:1.1.0-1.redhat_2.jbcs.el7, jbcs-httpd24-apr-1.6.3-14.jbcs.el7 +34
Show 1 more Red Hat advisories
- RHSA-2017:0906 Released 2017-04-12 · Red Hat rating Moderatehttpd security and bug fix update
- Red Hat Enterprise Linux Client Optional (v. 7) httpd-2.4.6-45.el7_3.4, httpd-devel-2.4.6-45.el7_3.4, httpd-manual-2.4.6-45.el7_3.4 +5
- Red Hat Enterprise Linux ComputeNode Optional (v. 7) httpd-2.4.6-45.el7_3.4, httpd-devel-2.4.6-45.el7_3.4, httpd-manual-2.4.6-45.el7_3.4 +5
- Red Hat Enterprise Linux Server (v. 7) httpd-2.4.6-45.el7_3.4, httpd-devel-2.4.6-45.el7_3.4, httpd-manual-2.4.6-45.el7_3.4 +2
- Red Hat Enterprise Linux Server Optional (v. 7) mod_ldap-2.4.6-45.el7_3.4, mod_proxy_html-1:2.4.6-45.el7_3.4, mod_session-2.4.6-45.el7_3.4
- Red Hat Enterprise Linux Workstation (v. 7) httpd-2.4.6-45.el7_3.4, httpd-devel-2.4.6-45.el7_3.4, httpd-manual-2.4.6-45.el7_3.4 +2
- Red Hat Enterprise Linux Workstation Optional (v. 7) mod_ldap-2.4.6-45.el7_3.4, mod_proxy_html-1:2.4.6-45.el7_3.4, mod_session-2.4.6-45.el7_3.4
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 5 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat JBoss Enterprise Application Platform 6 | Affected | No fix yet |
| Red Hat JBoss Enterprise Web Server 2 | Affected | No fix planned: Will not fix |
| Red Hat JBoss Enterprise Web Server 3 | Affected | No fix planned: Out of support scope |
| Red Hat JBoss Web Server 3 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux Client Optional (v. 7) | Fixed | RHSA-2017:0906 |
| Red Hat Enterprise Linux ComputeNode Optional (v. 7) | Fixed | RHSA-2017:0906 |
| Red Hat Enterprise Linux Server (v. 7) | Fixed | RHSA-2017:0906 |
| Red Hat Enterprise Linux Server Optional (v. 7) | Fixed | RHSA-2017:0906 |
| Red Hat Enterprise Linux Workstation (v. 7) | Fixed | RHSA-2017:0906 |
| Red Hat Enterprise Linux Workstation Optional (v. 7) | Fixed | RHSA-2017:0906 |
| Red Hat JBoss Core Services | Fixed | RHSA-2018:2486 |
| Red Hat JBoss Core Services on RHEL 6 Server | Fixed | RHSA-2018:2186 |
| Red Hat JBoss Core Services on RHEL 7 Server | Fixed | RHSA-2018:2185 |
Not affected: 2 products
- Red Hat Enterprise Linux 8
- Red Hat Software Collections
Timeline
- 2026-10-02 Threatist record created from CVE-2016-4975
- 2026-10-03 Alias added: GHSA-crcg-r773-w4rv
References
Advisory 3
Other 20
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbux03908en_us
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/
- [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.html
- [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.html
- [httpd-cvs] 20210330 svn commit: r1888194 [10/13] - /httpd/site/trunk/content/security/json/
- [httpd-cvs] 20210330 svn commit: r1073139 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/json/
- [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
- [httpd-cvs] 20210330 svn commit: r1073149 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/
- [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
- [httpd-cvs] 20210330 svn commit: r1073149 [10/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/
- [httpd-cvs] 20210603 svn commit: r1075360 [3/3] - 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/vulnerabilities_24.html
- [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/vulnerabilities_24.html
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Sources
- CVE-2016-4975 · CVE Program
- CVE-2016-4975 · NVD
- FIRST EPSS
- GHSA-crcg-r773-w4rv · GitHub Advisory Database · CC BY 4.0
- CVE-2016-4975 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences