CVE-2021-44224
HIGH8.2EPSS 9.3%Possible NULL dereference or SSRF in forward proxy configurations in Apache HTTP Server 2.4.51 and earlier
Published: 12/20/2021Modified: 4/28/2026
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).
Affected packages (5)
- Alpine/apache2from 0, < 2.4.52-r0
- Bitnami/apache>= 2.4.7, < 2.4.52
- Debian/apache2from 0, < 2.4.52-1~deb11u2
- Debian/apache2from 0, < 2.4.25-3+deb9u12
- Debian/apache2from 0, < 2.4.38-3+deb10u7
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
References (22)
- ADVISORYhttps://security.alpinelinux.org/vuln/CVE-2021-44224
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2021-44224
- WEBhttp://httpd.apache.org/security/vulnerabilities_24.html
- WEBhttp://seclists.org/fulldisclosure/2022/May/33
- WEBhttp://seclists.org/fulldisclosure/2022/May/35
- WEBhttp://seclists.org/fulldisclosure/2022/May/38
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BFSWOH4X77CV7AH7C4RMHUBDWKQDL4YH/
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGWILBORT67SHMSLYSQZG2NMXGCMPUZO/
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X73C35MMMZGBVPQQCH7LQZUMYZNQA5FO/
- WEBhttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7H26WJ6TPKNWV3QKY4BHKUKQVUTZJTD/
- WEBhttps://nvd.nist.gov/vuln/detail/CVE-2021-44224
- WEBhttps://security.gentoo.org/glsa/202208-20
- WEBhttps://security.netapp.com/advisory/ntap-20211224-0001/
- WEBhttps://support.apple.com/kb/HT213255
- WEBhttps://support.apple.com/kb/HT213256
- WEBhttps://support.apple.com/kb/HT213257
- WEBhttps://www.debian.org/security/2022/dsa-5035
- WEBhttps://www.oracle.com/security-alerts/cpuapr2022.html
- WEBhttps://www.oracle.com/security-alerts/cpujan2022.html
- WEBhttps://www.tenable.com/security/tns-2022-01
- WEBhttps://www.tenable.com/security/tns-2022-03
- WEBhttp://www.openwall.com/lists/oss-security/2021/12/20/3