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Fencer Intel
high 8.2

CVE-2021-44224 in the critical feed json

Possible NULL dereference or SSRF in forward proxy configurations in Apache HTTP Server 2.4.51 and earlier

published 4y ago modified 2mo ago also BIT-apache-2021-44224 , EUVD-2021-31073

cvss
8.2
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
82.3%
EPSS 82.3% chance of exploitation in 30 days, percentile 99.6%
public exploits
0
none known

Summary

A crafted URI sent to httpd configured as a forward proxy (ProxyRequests on) can cause a crash (NULL pointer dereference) or, for configurations mixing forward and reverse proxy declarations, can allow for requests to be directed to a declared Unix Domain Socket endpoint (Server Side Request Forgery). This issue affects Apache HTTP Server 2.4.7 up to 2.4.51 (included).

Patch / fix

  • bitnami apache 2.4.52
  • apache http_server 2.4.52
  • tenable tenable.sc 5.20.0, 202201.1
  • oracle communications_element_manager 9.0
  • oracle communications_session_report_manager 9.0
  • oracle communications_session_route_manager 9.0
  • apple macos 10.15.7, 11.6.6, 12.4
  • apache2 Debian 14, Debian 13, Debian 12 2.4.52-1

debian advisories DEBIAN-CVE-2021-44224

  • apache2 Ubuntu 18.04 LTS 2.4.29-1ubuntu4.21
  • apache2 Ubuntu 20.04 LTS 2.4.41-4ubuntu3.9
  • apache2 Ubuntu 22.04 LTS 2.4.52-1ubuntu1
  • apache2 Ubuntu Pro 14.04 LTS 2.4.7-1ubuntu4.22+esm3
  • apache2 Ubuntu Pro 16.04 LTS 2.4.18-2ubuntu3.17+esm4

ubuntu advisories UBUNTU-CVE-2021-44224

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • httpd24-httpd RHEL 3 SOFTWARE_COLLECTIONS 2.4.34-23.el7.5
  • httpd24-mod_ssl RHEL 3 SOFTWARE_COLLECTIONS 1:2.4.34-23.el7.5
  • httpd24-mod_ldap RHEL 3 SOFTWARE_COLLECTIONS 2.4.34-23.el7.5
  • httpd24-httpd-tools RHEL 3 SOFTWARE_COLLECTIONS 2.4.34-23.el7.5
  • httpd24-mod_session RHEL 3 SOFTWARE_COLLECTIONS 2.4.34-23.el7.5
  • httpd24-httpd-manual RHEL 3 SOFTWARE_COLLECTIONS 2.4.34-23.el7.5
  • httpd24-mod_proxy_html RHEL 3 SOFTWARE_COLLECTIONS 1:2.4.34-23.el7.5
  • httpd RHEL 8 2.4.37-47.module+el8.6.0+14529+083145da.1

red hat advisories RHSA-2022:6753RHSA-2022:1915RHSA-2022:7143

  • apache2 SLES for SAP 15 SP5, SLES for SAP 15 SP4, SLES 15 SP5-LTSS +5 more 2.4.66-150400.6.57.1
  • apache2 SLES for SAP 12 SP5, SLES 12 SP5, SLE Software Development Kit 12 SP5 2.4.51-35.7.1
  • apache2 SLE Module for Server Applications 15 SP3, SLE Module for Server Applications 15 SP2, SLE Module for Package Hub 15 SP3 +3 more 2.4.51-3.37.1
  • apache2 SLES for SAP 15 SP1, SLES for SAP 15, SLES 15-LTSS +7 more 2.4.33-3.61.1
  • apache2 SLES for SAP 12 SP4, SLES for SAP 12 SP3, SLES 12 SP4-LTSS +8 more 2.4.23-29.83.1

suse advisories SUSE-SU-2026:2686-1SUSE-SU-2022:0440-1SUSE-SU-2022:0091-2SUSE-SU-2022:0119-1SUSE-SU-2022:0091-1SUSE-SU-2022:0065-1

  • apache2 openSUSE Tumbleweed 2.4.52-1.1
  • apache2 openSUSE Leap 15.3 2.4.51-3.37.1
  • chromium Package Hub 15 SP3, openSUSE Leap 15.3 99.0.4844.84-bp153.2.75.1

opensuse advisories openSUSE-SU-2024:11695-1openSUSE-SU-2022:0091-1

  • httpd AlmaLinux 8 2.4.37-47.module_el8.6.0+2935+fb177b09.2
  • httpd AlmaLinux 8 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma
  • mod_md AlmaLinux 8 1:2.0.8-8.module_el8.6.0+2872+fe0ff7aa
  • mod_ssl AlmaLinux 8 1:2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma
  • mod_ssl AlmaLinux 8 1:2.4.37-47.module_el8.6.0+2935+fb177b09.2
  • mod_ldap AlmaLinux 8 2.4.37-47.module_el8.6.0+2935+fb177b09.2
  • mod_ldap AlmaLinux 8 2.4.37-47.module_el8.6.0+2872+fe0ff7aa.1.alma
  • mod_http2 AlmaLinux 8 1.15.7-5.module_el8.6.0+2872+fe0ff7aa

almalinux advisories ALSA-2022:1915

  • httpd Rocky Linux 8 2.4.37-47.module+el8.6.0+823+f143cee1.1
  • mod_md Rocky Linux 8 1:2.0.8-8.module+el8.5.0+695+1fa8055e
  • mod_md Rocky Linux 8 1:2.0.8-8.module+el8.4.0+553+7a69454b
  • mod_http2 Rocky Linux 8 1.15.7-5.module+el8.6.0+823+f143cee1

rocky linux advisories RLSA-2022:1915

  • apache2 Alpine 3.24, Alpine 3.23, Alpine 3.22 +10 more 2.4.52-r0

alpine advisories ALPINE-CVE-2021-44224

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • httpd CBL-Mariner 2.0 2.4.52-1

azure linux advisories AZL-7043

Azure Linux vulnerability data, Copyright (c) Microsoft Corporation, from https://github.com/microsoft/AzureLinuxVulnerabilityData via OSV, under the MIT licence; changed: normalised to fixed package versions per release. MIT

Is CVE-2021-44224 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-44224 updated cvss 7.1

httpd: possible NULL dereference or SSRF in forward proxy configurations

  • Red Hat JBoss Enterprise Application Platform 6 httpd, mod_ssl, mod_ldap, httpd-tools, httpd-manual
    affected: workaround, no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) mod_md 2.0.8-8.module+el8.3.0+6814+67d1e611, httpd 2.4.37-47.module+el8.6.0+14529+083145da.1, mod_http2 1.15.7-5.module+el8.6.0+13996+01710940, mod_ssl 2.4.37-47.module+el8.6.0+14529+083145da.1, mod_ldap 2.4.37-47.module+el8.6.0+14529+083145da.1, httpd-tools 2.4.37-47.module+el8.6.0+14529+083145da.1, +4 more
    fixed: vendor fix RHSA-2022:1915
  • Red Hat JBoss Core Services
    fixed: vendor fix RHSA-2022:7144
  • Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-httpd 2.4.51-28.el7jbcs, jbcs-httpd24-mod_ssl 2.4.51-28.el7jbcs, jbcs-httpd24-mod_ldap 2.4.51-28.el7jbcs, jbcs-httpd24-httpd-tools 2.4.51-28.el7jbcs, jbcs-httpd24-mod_session 2.4.51-28.el7jbcs, jbcs-httpd24-httpd-manual 2.4.51-28.el7jbcs, +2 more Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-httpd 2.4.51-28.el8jbcs, jbcs-httpd24-mod_ssl 2.4.51-28.el8jbcs, jbcs-httpd24-mod_ldap 2.4.51-28.el8jbcs, jbcs-httpd24-httpd-tools 2.4.51-28.el8jbcs, jbcs-httpd24-mod_session 2.4.51-28.el8jbcs, jbcs-httpd24-httpd-manual 2.4.51-28.el8jbcs, +2 more
    fixed: vendor fix RHSA-2022:7143
  • Red Hat Software Collections for RHEL Workstation(v. 7) httpd24-httpd 2.4.34-23.el7.5, httpd24-mod_ssl 2.4.34-23.el7.5, httpd24-mod_ldap 2.4.34-23.el7.5, httpd24-httpd-tools 2.4.34-23.el7.5, httpd24-mod_session 2.4.34-23.el7.5, httpd24-httpd-manual 2.4.34-23.el7.5, +1 more Red Hat Software Collections for RHEL(v. 7) httpd24-httpd 2.4.34-23.el7.5, httpd24-mod_ssl 2.4.34-23.el7.5, httpd24-mod_ldap 2.4.34-23.el7.5, httpd24-httpd-tools 2.4.34-23.el7.5, httpd24-mod_session 2.4.34-23.el7.5, httpd24-httpd-manual 2.4.34-23.el7.5, +1 more
    fixed: vendor fix RHSA-2022:6753
  • Red Hat Enterprise Linux 6 httpd, mod_ssl, httpd-tools, httpd-manual Red Hat Enterprise Linux 7 httpd, mod_ssl, mod_ldap, httpd-tools, mod_session, httpd-manual, +1 more Red Hat Enterprise Linux 9 httpd, mod_lua, mod_ssl, mod_ldap, httpd-core, httpd-tools, +4 more Red Hat JBoss Core Services on RHEL 7 Server jbcs-httpd24-apr 1.7.0-6.el7jbcs, jbcs-httpd24-curl 7.83.1-6.el7jbcs, jbcs-httpd24-brotli 1.0.9-2.el7jbcs, jbcs-httpd24-jansson 2.14-1.el7jbcs, jbcs-httpd24-mod_md 2.4.0-15.el7jbcs, jbcs-httpd24-libcurl 7.83.1-6.el7jbcs, +19 more Red Hat JBoss Core Services on RHEL 8 jbcs-httpd24-apr 1.7.0-6.el8jbcs, jbcs-httpd24-curl 7.83.1-6.el8jbcs, jbcs-httpd24-brotli 1.0.9-2.el8jbcs, jbcs-httpd24-jansson 2.14-1.el8jbcs, jbcs-httpd24-mod_md 2.4.0-15.el8jbcs, jbcs-httpd24-libcurl 7.83.1-6.el8jbcs, +19 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

82.30% chance of exploitation in the next 30 days, higher than 99.6% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
NVD 2.0 6.4 AV:N/AC:L/Au:N/C:N/I:P/A:P
OSV 3.1 8.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H

Affected packages

ecosystem package affected fixed in
bitnami apache
>=2.4.7, <2.4.52
2.4.52

Affected products

  • Apache Software Foundation Apache HTTP Server

Classification

Weakness
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.