Cyber Resilience

CVE-2021-31979

Memory Safety in Microsoft Windows Server 2008 r2

CISA KEVActive ExploitationEUVD ExploitedMemory Safety
Published
14 July 2021
Modified
10 August 2026
KEV Added
03 November 2021
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.045 91th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2021-31979 is a high-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Microsoft Windows Server 2008. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Process Injection (T1055); ranked in the top 9% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2021-31979 is a Windows Kernel Elevation of Privilege Vulnerability affecting the Windows kernel component and classified under CWE-119. It received a CVSS 3.1 score of 7.8 with the vector AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

An attacker with existing local access and low privileges can exploit the flaw without user interaction to elevate rights on the affected system, resulting in high impact to confidentiality, integrity, and availability.

Microsoft published mitigation details in its security advisory for CVE-2021-31979, and the vulnerability appears in the CISA catalog of known exploited vulnerabilities.

EU & UK References

Vulnerability Data

Windows Kernel Elevation of Privilege Vulnerability

CWE(s)
KEV Date Added
03 November 2021

Related Threats

MITRE ATT&CK Enterprise Techniques

T1055 Process Injection Stealth
Adversaries may inject code into processes in order to evade process-based defenses as well as possibly elevate privileges.
T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
T1203 Exploitation for Client Execution Execution
Adversaries may exploit software vulnerabilities in client applications to execute code.
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
T1212 Exploitation for Credential Access Credential Access
Adversaries may exploit software vulnerabilities in an attempt to collect credentials.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2019-1214Same product: Microsoft Windows 10 1507both on KEV
CVE-2017-0022Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-31956Same product: Microsoft Windows 10 1507both on KEV
CVE-2015-2546Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-40449Same product: Microsoft Windows 10 1507both on KEV
CVE-2014-6332Same product: Microsoft Windows 7both on KEV
CVE-2021-33742Same product: Microsoft Windows 10 1507both on KEV
CVE-2021-34448Same product: Microsoft Windows 10 1507both on KEV
CVE-2013-3660Same product: Microsoft Windows 7both on KEV
CVE-2020-17087Same product: Microsoft Windows 10 1507both on KEV

Affected Assets

microsoft
windows 10 1507
≤ 10.0.10240.19003
microsoft
windows 10 1607
≤ 10.0.14393.4530
microsoft
windows 10 1809
≤ 10.0.17763.2061
microsoft
windows 10 1909
≤ 10.0.18363.1679
microsoft
windows 10 2004
≤ 10.0.19041.1110
microsoft
windows 10 20h2
≤ 10.0.19042.1110
microsoft
windows 10 21h1
≤ 10.0.19043.1110
microsoft
windows 7
all versions
microsoft
windows 8.1
all versions
microsoft
windows rt 8.1
all versions
+6 more product configuration(s) — see NVD for full list

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V17.3.2

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-119

Ongoing control assessments and code testing (static/dynamic analysis, fuzzing) surface memory buffer restriction failures, which are then remediated before release.

addresses: CWE-119

Managed runtimes used by platform-independent applications (e.g., JVM, CLR) enforce memory safety, preventing most buffer overflows that require direct memory manipulation.

addresses: CWE-119

Memory protections (e.g., W^X, ASLR) make exploitation of buffer-boundary violations far harder to turn into code execution.

addresses: CWE-119

Detects exploitation attempts that produce memory corruption, crashes, or anomalous behavior.

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 (bounds checking, safe APIs, reviews) directly prevent this class of flaw.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis directly surface buffer-boundary flaws.

ID.RA-08 partial match
prevents

Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.

PR.AT-02 partial match
prevents

Developer training on secure coding reduces introduction of memory-buffer errors.

PR.PS-02 partial match
prevents

Patching replaces vulnerable code containing buffer-boundary defects.

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.

finds

Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.

prevents

Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.

prevents

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

prevents

Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.

prevents

Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.

References