Description
Apache HTTP Server versions 2.4.41 to 2.4.46 mod_proxy_http can be made to crash (NULL pointer dereference) with specially crafted requests using both Content-Length and Transfer-Encoding headers, leading to a Denial of Service
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache HTTP Server | 2.4.46, 2.4.43, 2.4.41 | — |
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 | 2.4.46-6 | — |
| Debian 13 | apache2 | 2.4.46-6 | — |
| Debian 12 | apache2 | 2.4.46-6 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | apache2 | 2.4.41-4ubuntu3.3 | USN-4994-1 |
| Ubuntu 18.04 LTS | apache2 | 2.4.29-1ubuntu4.16 | USN-4994-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | httpd +6 | 2.4.37-47.module+el8.6.0+15654+427eba2e.2 | RHSA-2022:5163 |
| RHEL 8 | mod_http2 | 1.15.7-5.module+el8.6.0+13996+01710940 | RHSA-2022:5163 |
| RHEL 8 | mod_md | 1:2.0.8-8.module+el8.3.0+6814+67d1e611 | RHSA-2022:5163 |
| RHEL 8 | mod_ssl +1 | 1:2.4.37-47.module+el8.6.0+15654+427eba2e.2 | RHSA-2022:5163 |
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 | 1.6.3-107.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-apr-util +8 | 1.6.1-84.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-curl +2 | 7.78.0-2.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-httpd +6 | 2.4.37-78.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_cluster-native | 1.3.16-9.Final_redhat_2.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_http2 | 1.15.7-21.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_jk +2 | 1.2.48-20.redhat_1.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_md | 1:2.0.8-40.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_security | 2.9.2-67.GA.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-mod_ssl +1 | 1:2.4.37-78.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-nghttp2 +1 | 1.39.2-39.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl +4 | 1:1.1.1g-8.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl-chil | 1.0.0-7.el8jbcs | RHSA-2021:4614 |
| Red Hat JBoss Core Services 1 | jbcs-httpd24-openssl-pkcs11 | 0.4.10-22.el8jbcs | RHSA-2021:4614 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | httpd | 2.4.37-47.module+el8.6.0+823+f143cee1.1 | RLSA-2022:5163 |
| Rocky Linux 8 | mod_http2 | 1.15.7-5.module+el8.6.0+823+f143cee1 | RLSA-2022:5163 |
| Rocky Linux 8 | mod_md | 1:2.0.8-8.module+el8.4.0+553+7a69454b | RLSA-2022:5163 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP3 | apache2 | 2.4.43-3.22.1 | SUSE-SU-2021:2127-1 |
| SLES 15 SP2 | apache2 | 2.4.43-3.22.1 | SUSE-SU-2021:2127-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.3 | apache2 | 2.4.43-3.22.1 | openSUSE-SU-2021:2127-1 |
| openSUSE Leap 15.2 | apache2 | 2.4.43-lp152.2.15.1 | openSUSE-SU-2021:0908-1 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | apache2 | 2.4.48-r0 | — |
| Alpine v3.23 | apache2 | 2.4.48-r0 | — |
| Alpine v3.22 | apache2 | 2.4.48-r0 | — |
| Alpine v3.21 | apache2 | 2.4.48-r0 | — |
| Alpine v3.20 | apache2 | 2.4.48-r0 | — |
Show 10 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | apache2 | 2.4.48-r0 | — |
| Alpine v3.18 | apache2 | 2.4.48-r0 | — |
| Alpine v3.17 | apache2 | 2.4.48-r0 | — |
| Alpine v3.16 | apache2 | 2.4.48-r0 | — |
| Alpine v3.15 | apache2 | 2.4.48-r0 | — |
| Alpine v3.14 | apache2 | 2.4.48-r0 | — |
| Alpine v3.13 | apache2 | 2.4.48-r0 | — |
| Alpine v3.12 | apache2 | 2.4.48-r0 | — |
| Alpine v3.11 | apache2 | 2.4.48-r0 | — |
| Alpine v3.10 | apache2 | 2.4.48-r0 | — |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | httpd +7 | 2.4.48-2.amzn2 | ALAS2-2021-1674 |
| Amazon Linux 2 | mod_ssl +1 | 1:2.4.48-2.amzn2 | ALAS2-2021-1674 |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 2 (CBL-Mariner) | httpd | 2.4.46-10 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | httpd +6 | 2.4.37-47.0.1.module+el8.6.0+20683+407db9f5.2 | ELSA-2022-5163 |
| Oracle Linux 8 | mod_http2 | 1.15.7-5.module+el8.6.0+20548+01710940 | ELSA-2022-5163 |
| Oracle Linux 8 | mod_md | 1:2.0.8-8.module+el8.5.0+20475+4f6a8fd5 | ELSA-2022-5163 |
| Oracle Linux 8 | mod_ssl +1 | 1:2.4.37-47.0.1.module+el8.6.0+20683+407db9f5.2 | ELSA-2022-5163 |
Advisories 11
- RHSA-2021:4614 Red Hat Security Advisory: Red Hat JBoss Core Services Apache HTTP Server 2.4.37 SP10 security update Red Hat Security Advisories (RHSA) · Oct 9, 2026
- RHSA-2022:5163 Red Hat Security Advisory: httpd:2.4 security update Red Hat Security Advisories (RHSA) · Sep 21, 2026
- USN-4994-1 apache2 vulnerabilities Ubuntu Security Notices (USN) · Apr 22, 2026
- RLSA-2022:5163 Low: httpd:2.4 security update Rocky Linux Security Advisories · Feb 5, 2026
- openSUSE-SU-2021:0908-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2021:2127-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:2127-1 Security update for apache2 SUSE / openSUSE Security Updates · Feb 4, 2026
- WID-SEC-2024-1591 Juniper JUNOS: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2024
- WID-SEC-2022-0438 Apache HTTP Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · May 26, 2024
- ELSA-2022-5163 Low: httpd:2.4 security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Jun 24, 2022
- ALAS2-2021-1674 Moderate: httpd security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Jul 1, 2021
References
- http://httpd.apache.org/security/vulnerabilities_24.html
- https://lists.apache.org/thread.html/re026d3da9d7824bd93b9f871c0fdda978d960c7e62d8c43cba8d0bf3%40%3Ccvs.httpd.apache.org%3E
- [httpd-announce] 20210609 CVE-2020-13950: mod_proxy_http NULL pointer dereference mailing-list
- [httpd-dev] 20210610 Re: svn commit: r1890598 - in /httpd/site/trunk/content/security/json: CVE-2019-17567.json CVE-2020-13938.json CVE-2020-13950.json CVE-2020-35452.json CVE-2021-26690.json CVE-2021-26691.json CVE-2021-30641.json CVE-2021-31618.jso mailing-list
- [oss-security] 20210609 CVE-2020-13950: Apache httpd: mod_proxy_http NULL pointer dereference mailing-list
- GLSA-202107-38 vendor-advisory
- FEDORA-2021-dce7e7738e vendor-advisory
- FEDORA-2021-e3f6dd670d vendor-advisory
- https://www.oracle.com/security-alerts/cpuoct2021.html
- https://security.netapp.com/advisory/ntap-20210702-0001/