NULL pointer dereference in Apache HTTP Server
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 Domain Socket endpoint (Server Side Request Forgery). This issue affects Apache HTTP Server 2.4.7 up to 2.4.51 (included).
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.2 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H.
EPSS exploit prediction
EPSS: 0.823 (99.7th percentile), scored .
High probability of exploitation in the next 30 days — patch promptly. 100th percentile — 99.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.823 · newest: 0.823 · change: 0.000
Affected products
- Apache HTTP Server
- Apache Software Foundation HTTP Server — versions 2.4.7
- Apple macOS
- Apple Mac OS X — versions 10.15.7
- Oracle Communications Element Manager
- Oracle Communications Operations Monitor — versions 4.0, 4.3, 4.4
- Oracle Communications Session Report Manager
- Oracle Communications Session Route Manager
- Oracle HTTP Server — versions 12.2.1.3.0, 12.2.1.4.0
- Oracle Instantis Enterprisetrack — versions 17.1, 17.2, 17.3
Weakness classification (CWE)
Public proof-of-concept exploits
References
- httpd.apache.org/security/vulnerabilities_24.html (Vendor Advisory)
- www.openwall.com/lists/oss-security/2021/12/20/3 (mailing-list, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- www.debian.org/security/2022/dsa-5035 (vendor-advisory, Third Party Advisory)
- www.oracle.com/security-alerts/cpujan2022.html (Patch, Third Party Advisory)
- security.netapp.com/advisory/ntap-20211224-0001/ (Third Party Advisory)
- www.tenable.com/security/tns-2022-01 (Third Party Advisory)
- www.tenable.com/security/tns-2022-03 (Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
Frequently asked questions
- What is CVE-2021-44224?
- CVE-2021-44224 is a high-severity vulnerability in Apache HTTP Server, classified under NULL Pointer Dereference. CVSS score: 8.2/10. Published 2021-12-20.
- How severe is CVE-2021-44224?
- High severity. CVSS v3 base score is 8.2 out of 10.
- Is CVE-2021-44224 known to be exploited?
- 15 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.