CVE-2021-44224: apache software foundation apache http server NULL Pointer Dereference
Vulnerability summary
CVE-2021-44224 is a high (CVSS 8.2) NULL Pointer Dereference vulnerability in apache software foundation apache http server. EPSS estimates a 82.30% chance of exploitation in the next 30 days, higher than 99.6% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 16 · Related 10Timeline
- 20-12-2021PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
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).
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- OSV · UbuntuEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- OSV · DebianEcosystem advisory · calculated8.2HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS trend
Probability
82.30%
Chance of exploitation in the next 30 days
Percentile
100%
Versus all other CVEs
30-day change
0.00 pp
From 82.30% on 18-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Oracle6 products
- communications_element_manager< 9.0
- communications_operations_monitor4.0 | 4.3 | 4.4 | 5.0
- communications_session_report_manager< 9.0
- communications_session_route_manager< 9.0
- http_serverna | 12.2.1.3.0 | 12.2.1.4.0
Apple2 products
- mac_os_x10.15.7 | 10.15.7:security_update_2020-001 | 10.15.7:security_update_2021-001 | 10.15.7:security_update_2021-002 | 10.15.7:security_update_2021-003 | 10.15.7:security_update_2021-004 | 10.15.7:security_update_2021-005 | 10.15.7:security_update_2021-006 | 10.15.7:security_update_2021-007 | 10.15.7:security_update_2021-008 | 10.15.7:security_update_2022-001 | 10.15.7:security_update_2022-002 | 10.15.7:security_update_2022-003
- macos< 10.15.7 | ≥ 11.0, < 11.6.6 | ≥ 12.0.0, < 12.4
Debian2 products
- apache2< 2.4.52-1
- debian_linuxEOL10.0 | 11.0
Alpine1 product
- apache2< 2.4.52-r0
Apache1 product
- http_server≥ 2.4.7, < 2.4.52
Apache software foundation1 product
- apache http server≥ 2.4.7, < Apache HTTP Server 2.4*
Fedoraproject1 product
- fedoraEOL34 | 35 | 36
Tenable1 product
- tenable.sc≥ 5.14.0, < 5.20.0 | ≥ 5.16.0, < 202201.1
Ubuntu1 product
- apache2< 2.4.7-1ubuntu4.22+esm3 | < 2.4.18-2ubuntu3.17+esm4 | < 2.4.29-1ubuntu4.21 | < 2.4.41-4ubuntu3.9 | < 2.4.52-1ubuntu1
9 vendors · 16 products
