Description
In Apache HTTP Server 2.4.32-2.4.39, when mod_remoteip was configured to use a trusted intermediary proxy server using the "PROXY" protocol, a specially crafted PROXY header could trigger a stack buffer overflow or NULL pointer deference. This vulnerability could only be triggered by a trusted proxy and not by untrusted HTTP clients.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| — | Apache HTTP Server | 2.4.32 to 2.4.39 | — |
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 | 2.4.41-1 | — |
| Debian 13 | apache2 | 2.4.41-1 | — |
| Debian 12 | apache2 | 2.4.41-1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | httpd +6 | 2.4.37-30.module+el8.3.0+7001+0766b9e7 | RHSA-2020:4751 |
| RHEL 8 | mod_http2 | 1.15.7-2.module+el8.3.0+7670+8bf57d29 | RHSA-2020:4751 |
| RHEL 8 | mod_md | 1:2.0.8-8.module+el8.3.0+6814+67d1e611 | RHSA-2020:4751 |
| RHEL 8 | mod_ssl +1 | 1:2.4.37-30.module+el8.3.0+7001+0766b9e7 | RHSA-2020:4751 |
| RHEL 3 | httpd24 +3 | 1.1-19.el6 | RHSA-2019:4126 |
| RHEL 3 | httpd24-httpd +5 | 2.4.34-15.el6 | RHSA-2019:4126 |
| RHEL 3 | httpd24-mod_md | 2.4.34-15.el7 | RHSA-2019:4126 |
| RHEL 3 | httpd24-mod_ssl +1 | 1:2.4.34-15.el6 | RHSA-2019:4126 |
| RHEL 3 | httpd24-nghttp2 +2 | 1.7.1-8.el6 | RHSA-2019:4126 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apr +1 | 1.6.3-86.jbcs.el6 | RHSA-2020:1337 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-brotli +1 | 1.0.6-21.jbcs.el6 | RHSA-2020:1337 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.37-52.jbcs.el6 | RHSA-2020:1337 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_cluster-native | 1.3.12-41.Final_redhat_2.jbcs.el6 | RHSA-2020:1337 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_http2 | 1.11.3-22.jbcs.el6 | RHSA-2020:1337 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.37-52.jbcs.el6 | RHSA-2020:1337 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.1.1c-16.jbcs.el6 | RHSA-2020:1337 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | mod_md | 1:2.0.8-8.module_el8.5.0+2609+b30d9eec | ALSA-2020:4751 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | mod_md | 1:2.0.8-8.module+el8.4.0+553+7a69454b | RLSA-2020:4751 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | apache2 | 2.4.33-3.21.1 | SUSE-SU-2019:2237-1 |
| SLES 15 | apache2 | 2.4.33-3.21.1 | SUSE-SU-2019:2237-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | apache2 | 2.4.49-1.1 | openSUSE-SU-2024:10623-1 |
| openSUSE Leap 15.1 | apache2 | 2.4.33-lp151.8.6.1 | openSUSE-SU-2019:2051-1 |
| openSUSE Leap 15.0 | apache2 | 2.4.33-lp151.8.6.1 | openSUSE-SU-2019:2051-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | apache2 | 2.4.41-r0 | — |
| Alpine v3.23 | apache2 | 2.4.41-r0 | — |
| Alpine v3.22 | apache2 | 2.4.41-r0 | — |
| Alpine v3.21 | apache2 | 2.4.41-r0 | — |
| Alpine v3.20 | apache2 | 2.4.41-r0 | — |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | apache2 | 2.4.41-r0 | — |
| Alpine v3.18 | apache2 | 2.4.41-r0 | — |
| Alpine v3.17 | apache2 | 2.4.41-r0 | — |
| Alpine v3.16 | apache2 | 2.4.41-r0 | — |
| Alpine v3.15 | apache2 | 2.4.41-r0 | — |
| Alpine v3.14 | apache2 | 2.4.41-r0 | — |
| Alpine v3.13 | apache2 | 2.4.41-r0 | — |
| Alpine v3.12 | apache2 | 2.4.41-r0 | — |
| Alpine v3.11 | apache2 | 2.4.41-r0 | — |
| Alpine v3.10 | apache2 | 2.4.41-r0 | — |
| Alpine v3.9 | apache2 | 2.4.41-r0 | — |
| Alpine v3.8 | apache2 | 2.4.41-r0 | — |
| Alpine v3.7 | apache2 | 2.4.41-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | httpd +7 | 2.4.41-1.amzn2.0.1 | ALAS2-2019-1341 |
| Amazon Linux 2 | mod_ssl +1 | 1:2.4.41-1.amzn2.0.1 | ALAS2-2019-1341 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | httpd +6 | 2.4.37-30.0.1.module+el8.3.0+7816+49791cfd | ELSA-2020-4751 |
| Oracle Linux 8 | mod_http2 | 1.15.7-2.module+el8.3.0+7816+49791cfd | ELSA-2020-4751 |
| Oracle Linux 8 | mod_md | 1:2.0.8-8.module+el8.3.0+7816+49791cfd | ELSA-2020-4751 |
| Oracle Linux 8 | mod_ssl +1 | 1:2.4.37-30.0.1.module+el8.3.0+7816+49791cfd | ELSA-2020-4751 |
Advisories 11
- ALSA-2020:4751 Moderate: httpd:2.4 security, bug fix, and enhancement update AlmaLinux Security Advisories · Nov 2, 2026
- RHSA-2020:4751 Red Hat Security Advisory: httpd:2.4 security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2020:1337 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP2 security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RHSA-2019:4126 Red Hat Security Advisory: httpd24-httpd security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- RLSA-2020:4751 Moderate: httpd:2.4 security, bug fix, and enhancement update Rocky Linux Security Advisories · Feb 5, 2026
- openSUSE-SU-2019:2051-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2019:2237-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:10623-1 apache2-2.4.49-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-1591 Juniper JUNOS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2024
- ELSA-2020-4751 Moderate: httpd:2.4 security, bug fix, and enhancement update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Nov 10, 2020
- ALAS2-2019-1341 Moderate: httpd security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Oct 30, 2019
References
- RHSA-2019:4126 vendor-advisory
- [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
- https://www.oracle.com/security-alerts/cpuapr2020.html
- https://www.oracle.com/security-alerts/cpujul2020.html
- https://www.oracle.com/technetwork/security-advisory/cpuoct2019-5072832.html
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://www.oracle.com/security-alerts/cpuoct2020.html
- [httpd-cvs] 20210330 svn commit: r1073139 [1/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1073143 [3/3] - in /websites/staging/httpd/trunk/content: ./ security/ 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: r1073139 [12/13] - in /websites/staging/httpd/trunk/content: ./ security/json/ mailing-list
- [httpd-cvs] 20210330 svn commit: r1888194 [12/13] - /httpd/site/trunk/content/security/json/ 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 [13/13] - in /websites/staging/httpd/trunk/content: ./ security/ security/json/ mailing-list
- [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/vulnerabiliti mailing-list
- [httpd-cvs] 20210606 svn commit: r1075470 [4/4] - 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