CVE-2023-21745
CVE-2023-21745 is a high-severity vulnerability in Microsoft Exchange Server with a CVSS 3.x base score of 8.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-502.
Key facts
- Severity: High (CVSS 3.x base score 8.0)
- EPSS exploit prediction: 1% (71st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-502
- Affected product: Microsoft Exchange Server
- Published:
- Last modified:
Description
Microsoft Exchange Server Spoofing Vulnerability
Frequently asked questions
- What is CVE-2023-21745?
- Microsoft Exchange Server Spoofing Vulnerability
- How severe is CVE-2023-21745?
- CVE-2023-21745 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over an adjacent network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2023-21745 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (71st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2023-21745?
- CVE-2023-21745 primarily affects Microsoft Exchange Server. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2023-21745?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2023-21745 published?
- CVE-2023-21745 was published on 2023-01-10 and last updated on 2026-06-17.
References
Affected products (3)
- cpe:2.3:a:microsoft:exchange_server:2016:cumulative_update_23:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_11:*:*:*:*:*:*
- cpe:2.3:a:microsoft:exchange_server:2019:cumulative_update_12:*:*:*:*:*:*
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