Cyber Resilience

CVE-2021-44224

Memory Safety in Apple Mac Os X 10.15.7

High EPSSMemory Safety
Published
20 December 2021
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v3.1 8.2
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
EPSS Score 0.82 99.6th percentile
Risk Priority 85 floored blend · peak EPSS

Summary

CVE-2021-44224 is a high-severity NULL Pointer Dereference (CWE-476) vulnerability in Apple Mac Os X. Its CVSS base score is 8.2 (High).

Operationally, ranked in the top 0.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

A10:2025 Mishandling of Exceptional Conditions

EU & UK References

Vulnerability Data

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…

more

Domain Socket endpoint (Server Side Request Forgery). This issue affects Apache HTTP Server 2.4.7 up to 2.4.51 (included).

CWE(s)
CWE-476

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
Crafted URI to a forward proxy enables SSRF to Unix Domain Socket endpoints, directly exploiting a public-facing Apache HTTP Server.
attack.mitre.org →
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2021-44790Same product: Apache Http Server
CVE-2023-39351Same product: Debian Debian Linux
CVE-2023-46838Same product: Debian Debian Linux
CVE-2023-41358Same product: Debian Debian Linux
CVE-2023-41909Same product: Debian Debian Linux
CVE-2024-27399Same product: Debian Debian Linux
CVE-2023-1667Same product: Debian Debian Linux
CVE-2023-3772Same product: Debian Debian Linux
CVE-2023-3212Same product: Debian Debian Linux
CVE-2026-33007Same product: Apache Http Server

Affected Assets

apache
http server
2.4.7 — 2.4.52
fedoraproject
fedora
34, 35, 36
debian
debian linux
10.0, 11.0
tenable
tenable.sc
5.14.0 — 5.20.0 · 5.16.0 — 202201.1
oracle
communications element manager
≤ 9.0
oracle
communications operations monitor
4.0, 4.3, 4.4, 5.0
oracle
communications session report manager
≤ 9.0
oracle
communications session route manager
≤ 9.0
oracle
http server
12.2.1.3.0, 12.2.1.4.0, all versions
oracle
instantis enterprisetrack
17.1, 17.2, 17.3
+2 more product configuration(s) — see NVD for full list

Mitigating Controls

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing can detect NULL dereference defects before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.

A.8.26 Application security requirements partial match
prevents

Application security requirements can specify input validation and pointer-safety rules.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles encourage defensive design that avoids unsafe pointer use.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly require NULL-pointer checks and safe dereference patterns.

References