CVE-2023-21709 Details
A vulnerability was found in Microsoft Exchange Server 2016 CU23/2019 CU12/2019 CU13 (Groupware Software). It has been classified as very critical. Affected is some unknown processing. Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.
View at NVD
Exploit prediction scoring system (EPSS) score for CVE-2023-21709
EPSS (Exploit Prediction Scoring System): EPSS predicts the likelihood that a vulnerability will be exploited in the wild. A higher percentage means a greater chance of an exploit occurring. The EPSS model produces a probability score between 0 and 1 (0 and 100%).
3.58 Probability of exploitation activity being observed over the next 30 days (87th percentile)
CVSS score for CVE-2023-21709
CVSS (Common Vulnerability Scoring System): An open framework owned and managed by FIRST.Org, Inc. that assigns a numerical score from 0 to 10 to software vulnerabilities to indicate their severity.
9.8 Critical
Products affected by CVE-2023-21709
Exchange Server 2016
Exchange Server 2019
DVE Score by Bitsight AI
DVE scores complement traditional static scoring systems like CVSS with Bitsight AI powered real-time threat intelligence and underground cyber criminal activity so that security teams can reduce alert fatigue and focus on vulnerabilities most likely to be exploited.
Not available
More on DVE scores

CVE-2023-21709 Global Footprint

Top 10 Identified Countries

Country Observations Percentage
FR 2,162 21.43%
US 1,427 14.14%
DE 1,226 12.15%
RU 923 9.15%
IT 415 4.11%
GB 398 3.94%
CN 281 2.78%
AT 234 2.32%
AU 194 1.92%
CA 173 1.71%

Is CVE-2023-21709 part of your extended attack surface? Bitsight helps security leaders rapidly identify exposure and detect threats in order to prioritize, communicate, and mitigate risk.

View interactive product tours

CVE-2023-21709 Industry Footprint

Top 10 Identified Industries

*Service provider organizations (typically Technology and Telecommunications) are disproportionally represented in the results given their upstream ownership of end-user infrastructure. See our FAQs.

Industry* Observations Percentage
Telecommunications 3,079 72.98%
Technology 644 15.26%
Manufacturing 68 1.61%
Government/Politics 66 1.56%
Business Services 50 1.19%
Energy/Resources 45 1.07%
Utilities 45 1.07%
Finance 35 0.83%
Engineering 28 0.66%
Education 25 0.59%

Bitsight Data Discovery and Continuous Threat Scanning

Bitsight, the leading provider in Cyber Risk Management, introduced the next-generation internet scanner Bitsight Groma in May 2024. This technology continuously scans the entire internet to discover assets, collect asset attribution evidence, and identify an ever-growing set of security observations, such as vulnerabilities and misconfigurations. Groma’s scanning activities presently encompass:


  • 40 million-plus monitored organizations
  • 250 million-plus host names
  • 4 billion-plus routable IPv4 and IPv6 addresses

Greynoise’s recent study testifies the speed of Bitsight Groma.

Learn more about Bitsight Groma
Bitsight data discovery
Governance charcoal background

How we use Bitsight Groma data 

Empower Security Research

Bitsight TRACE team investigates security incidents and identifies vulnerabilities and threats.

View latest security research 

See Your External Attack Surface

See what you’re up against across the expanding attack surface. Prioritize what matters most. And mitigate where you’re most vulnerable.

External Attack Surface Management

Bitsight ASA Report Image

Your attack surface is expanding—know exactly how it looks

Reducing exposure starts with knowing exactly how your external attack surface stands—from your overall standing to each digital and cloud asset around the world. Bitsight's custom report gives you the insights you need to see your entire external attack surface.

Get a free attack surface report