CVE-2021-42321
Microsoft Exchange Server 2016 … 2019
Raw vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSummary
CVE-2021-42321 is a high-severity an unspecified weakness vulnerability in Microsoft Exchange Server. Its CVSS base score is 8.8 (High).
Operationally, ranked in the top 0.2% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.
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-2021-42321 is a remote code execution vulnerability affecting Microsoft Exchange Server. It carries a CVSS 3.1 base score of 8.8 with an attack vector of network, low attack complexity, low privileges required, no user interaction, and high impact to confidentiality, integrity, and availability.
An authenticated attacker can exploit the flaw over the network to achieve arbitrary code execution on the affected server. The vulnerability is tracked under NVD-CWE-Other and was publicly disclosed on 10 November 2021.
Microsoft publishes mitigation guidance in its security advisory at https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-42321. Public exploit code targeting the issue, including chained serialization binder techniques, has been posted to PacketStorm Security.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2021-29296
Vulnerability Data
Microsoft Exchange Server Remote Code Execution Vulnerability
- CWE(s)
- KEV Date Added
- 17 November 2021
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Affected Assets
Mitigating Controls
No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.