Page generated: 09 Nov 2026, 06:50 UTC
CVE-2021-33766
Microsoft Exchange Server Information Disclosure Vulnerability
CVSS 7.3 (HIGH) KEV: KNOWN CATALOG
Attention and evidence
HYPE SCORE
0.0/10
REALITY · THREAT PRIORITY
8.6/10
General review priority; not probability
Evidence confidence: Exploitation recorded
Sources: 10 documents and public datasets.
Hype components
Headline sample (25%)
0/100
Press, 30 days (60%)
0/100
Grounded branding (15%)
0/100
HYPE TOTAL0/100
Sources and documents
Unit 42
Press · 28 Jun 2023, 07:00 · Manic Menagerie 2.0: The Evolution of a Highly Motivated Threat Actor - Unit 42
Qualys
Press · 22 Feb 2022, 08:00 · Managing CISA Known Exploited Vulnerabilities with Qualys VMDR - Qualys
BleepingComputer
Press · 22 Jan 2022, 08:00 · CISA adds 17 vulnerabilities to list of bugs exploited in attacks - BleepingComputer
Arctic Wolf
Press · 03 Sep 2021, 07:00 · ProxyToken: Authentication Bypass Vulnerability in On-Premises Microsoft Exchange - Arctic Wolf
The Hacker News
Press · 31 Aug 2021, 07:00 · New Microsoft Exchange 'ProxyToken' Flaw Lets Attackers Reconfigure Mailboxes - The Hacker News
Score evolution
● Hype ● Reality
Earlier evidence-support scores are retained in history; this chart shows only the current priority definition.
First record: hype 0.0 · reality 8.6 (2026-11-02 15:12). The curve appears once the score changes.
Public exploit evidence
2
Public exploit entries / repo candidates
Evidence context and dated references
Reality is general threat/review priority, combining observed exploitation, CVSS severity and fresh EPSS. Evidence confidence is separate. This is not calibrated risk, a victim count or an asset-specific assessment. A range reflects missing numeric inputs.
Evidence in context
- Confidence in exploitation evidence
- Exploitation recorded
- Priority basis
- Recorded exploitation; CVSS 7.3; EPSS 98.2%
- Attention, last 30 days
- 0 distinct story titles; 0 press documents; 0 publisher domains.
- Technical potential
- network access, no prior privileges, no user interaction.
- Observed activity
- Exploitation recorded in CISA KEV.
- Known scale
- Not quantified.
- Evidence confidence basis
- Trusted exploitation confirmation
Score evaluated: 2026-11-05 13:58:27.921902+00:00 · EPSS snapshot: 2026-11-05T12:03:04Z
Source event timeline
First press mention
13 Jul 2021, 07:00
Published
14 Jul 2021, 17:53
Added to the CISA KEV catalog
18 Jan 2022, 00:00
Latest press mention
28 Jun 2023, 07:00
Score calculated
05 Nov 2026, 13:58
PoCs on GitHub
2 repositories