CVE-2021-44224
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…
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 82.3%, higher than 100% of all known CVEs. Patch or mitigate before the next change window.
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 3.1
- 8.2 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
- EPSS
- 82.30% probability · 100th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-476
- Affected
- apache/http server · fedoraproject/fedora · debian/debian linux · tenable/tenable.sc · oracle/communications element manager · oracle/communications operations monitor · oracle/communications session report manager · oracle/communications session route manager · oracle/http server · oracle/instantis enterprisetrack · apple/mac os x · apple/macos
- Source
- security@apache.org
EPSS 82.3% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- http://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
- http://seclists.org/fulldisclosure/2022/May/33Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/35Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/38Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/12/20/3Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BFSWOH4X77CV7AH7C4RMHUBDWKQDL4YH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGWILBORT67SHMSLYSQZG2NMXGCMPUZO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X73C35MMMZGBVPQQCH7LQZUMYZNQA5FO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7H26WJ6TPKNWV3QKY4BHKUKQVUTZJTD/
- https://security.gentoo.org/glsa/202208-20Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211224-0001/Third Party Advisory
- https://support.apple.com/kb/HT213255Third Party Advisory
- https://support.apple.com/kb/HT213256Third Party Advisory
- https://support.apple.com/kb/HT213257Third Party Advisory
- https://www.debian.org/security/2022/dsa-5035Third Party Advisory
- https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
- https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory
- https://www.tenable.com/security/tns-2022-01Third Party Advisory
- https://www.tenable.com/security/tns-2022-03Third Party Advisory
- http://httpd.apache.org/security/vulnerabilities_24.htmlVendor Advisory
- http://seclists.org/fulldisclosure/2022/May/33Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/35Mailing List, Third Party Advisory
- http://seclists.org/fulldisclosure/2022/May/38Mailing List, Third Party Advisory
- http://www.openwall.com/lists/oss-security/2021/12/20/3Mailing List, Third Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BFSWOH4X77CV7AH7C4RMHUBDWKQDL4YH/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RGWILBORT67SHMSLYSQZG2NMXGCMPUZO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X73C35MMMZGBVPQQCH7LQZUMYZNQA5FO/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/Z7H26WJ6TPKNWV3QKY4BHKUKQVUTZJTD/
- https://security.gentoo.org/glsa/202208-20Third Party Advisory
- https://security.netapp.com/advisory/ntap-20211224-0001/Third Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.