CVE-2021-34473
ProxyShell: Remote Code Execution in Microsoft Exchange Server Autodiscover API
⚡ KEV — Known Exploited
CVSS 9.8 (Critical)
EPSS 0.9720 (1th pct)
Technical Description
ProxyShell: Remote Code Execution in Microsoft Exchange Server Autodiscover API.
Why this matters to your organisation:
CISA has confirmed active exploitation in the wild (KEV catalogue entry). The Exploit Prediction Scoring System (EPSS) estimates a 97.2% probability of exploitation within 30 days. The affected service is internet-facing, increasing exposure. This is a critical service for the organisation.
CISA has confirmed active exploitation in the wild (KEV catalogue entry). The Exploit Prediction Scoring System (EPSS) estimates a 97.2% probability of exploitation within 30 days. The affected service is internet-facing, increasing exposure. This is a critical service for the organisation.
Potential Impact
A vulnerability in exchange_server rated Critical (CVSS 9.8). This vulnerability is listed in CISA's Known Exploited Vulnerabilities catalogue, indicating it has been actively exploited in the wild.
✅ Recommended Next Action
Review CVE-2021-34473 and confirm whether exchange_server is in use.
Confidence: Not Applicable
The organisation does not use this product.
CVE Details
| Product | microsoft exchange_server |
| Version Range | <= 15.1.2242 → ∞ |
| Installed | Unknown |
| Match Type | Product Not Used |
| CVSS | 9.8 |
| KEV | YES |
| EPSS | 0.972 |
| Source |
NVD · July 13, 2021 View reference ↗ |
Score Breakdown
⚡ KEV+40
🌐 Exposure+20
⭐ Importance+15
📈 EPSS+14.6
🔢 CVSS+9.8
⚠ Uncertainty-10
Total89