CVE-2026-21224
Published: 13 January 2026
Summary
CVE-2026-21224 is a high-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Microsoft Azure Connected Machine Agent. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 16.4th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 SI-10 (Information Input Validation) and SI-16 (Memory Protection).
Deeper analysis
CVE-2026-21224, published on 2026-01-13, is a stack-based buffer overflow vulnerability (CWE-121) in the Azure Connected Machine Agent. The issue carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity due to its potential for significant impact with relatively low barriers to exploitation.
A local attacker with low privileges (PR:L) can exploit this vulnerability by triggering the buffer overflow in the Azure Connected Machine Agent. Exploitation requires only local access and low attack complexity, with no user interaction needed. Successful exploitation allows the attacker to elevate privileges locally, achieving high impacts on confidentiality, integrity, and availability.
Mitigation details are available in the Microsoft Security Response Center advisory at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-21224.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-2110
Vulnerability details
Stack-based buffer overflow in Azure Connected Machine Agent allows an authorized attacker to elevate privileges locally.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Stack-based buffer overflow in local Azure agent directly enables local privilege escalation via exploitation of a vulnerable process.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Requires timely remediation of known vulnerabilities like the stack-based buffer overflow in Azure Connected Machine Agent via patching.
Implements memory protections such as ASLR, DEP, and stack canaries that directly thwart stack-based buffer overflow exploits.
Mandates validation of information inputs to the Azure Connected Machine Agent, preventing buffer overflows from malformed or oversized data.