CVE-2021-28480
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Microsoft Exchange Server Remote Code Execution Vulnerability
rank 59 = 26 + 25 + 3 + 5 + 0
rank@v1 · this cycle
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.71227 · without this subject the record ranks 33
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 10.0, from NVD · without this subject the record ranks 34
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
rose on 2026-02-18 · without this subject the record ranks 56
How much of the world it touches
NVD CPE configurations
3 products in the CPE ranges · without this subject the record ranks 54
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 59
$3.55M = $4.99M incident cost x 1 exposure x 0.71227 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
Sources disagree here.
Both shown, dated. We don't pick winners. disagreement-rules@v1
Running Microsoft Exchange Server 2013 Cumulative…? Check your version
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Harm, if it fires from the vector and the weakness
Written for the ticket you're about to file.
CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Proof-of-concept published · 1 public repository, 2021-04-21.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published · 1 public repository2021-04-21receipt
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
Affected & Fixed Versions as published
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
What it is stated by the CNA
Microsoft Exchange Server Remote Code Execution Vulnerability receipt
NVD's analysis a second authority
- severity
- 10 AV:N/AC:L/Au:N/C:C/I:C/A:C
- affected versions
- microsoft exchange server 2013; microsoft exchange server 2016; microsoft exchange server 2019
- also scored by
- [email protected] 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H · [email protected] 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
The CNA scored it 9.8 and NVD 10. Both are shown because both were published; we do not pick one.
check it yourself portal.msrc.microsoft.com receipt
Dated events
Movement the material steps
This score more than doubled inside 72 hours. Both observations are in the full history below.
Show all 60 observations
60 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
Siblings and hubs
Records related to this one
No record cites this identifier and it carries no alias. Its defect family is below.
Its defect family
microsoft exchange server 2013 cumulative update 23
Of the 12 records in this family, this is the only one holding a stated fix version: 15.00.1497.015; 15.01.2176.012; 15.02.0792.013; 15.01.2242.0.
Grouped by shared product and weakness, not by shared vulnerability. Each record's own state is on its own page.
Family membership: held values
This record is one of a group, and the group's page describes all of them. This page is kept and dated, and the defect family's own page is the one we offer for indexing: the whole group.
Browse the index from here
These are index-wide views, not findings about CVE-2021-28480.
What usually comes next
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