CVE-2009-0099Exchange Server Vulnerability
The Electronic Messaging System Microsoft Data Base (EMSMDB32) provider in Microsoft Exchange 2000 Server SP3 and Exchange Server 2003 SP2, as used in Exchange System Attendant, allows remote attackers to cause a denial of service (application outage) via a malformed MAPI…
Published Feb 10, 2009 · Updated Apr 22, 2026
Key Facts
Patch immediately- CVE-2009-0099 is a medium-severity vulnerability (CVSS 5.0 v2) affecting Exchange Server (Microsoft).
- It is exploited in the wild, listed in Industry KEV feed since Jun 20, 2017. No public exploit code is known.
- EPSS estimates a 26% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Scores
CVSS v2
5.0
AV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS (30-day exploit likelihood)
26%
Higher than 98.0% of all scored CVEs
Exploit maturity
Exploited (KEV)
ATLAS score
54/100
Publication score, see How it works
Exploitation Verdict
KEV listed
Jun 20, 2017
3052 days after publication
Federal due date
None
No federal due date
Ransomware use
Not reported
Attributed actors
None named
Exploit & Defence Guidance
Exploit maturity
Exploited (KEV)
Public exploit code
0
Proof-of-concept links
In-the-wild evidence
1
Reports of active use
Description
The Electronic Messaging System Microsoft Data Base (EMSMDB32) provider in Microsoft Exchange 2000 Server SP3 and Exchange Server 2003 SP2, as used in Exchange System Attendant, allows remote attackers to cause a denial of service (application outage) via a malformed MAPI command, aka "Literal Processing Vulnerability."
Known-Exploited Catalog Listings
| Catalog | Added | Remediation due | Ransomware use |
|---|---|---|---|
| Industry KEV feed | Jun 20, 2017 | n/a | Not reported |
Affected Products
3 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Exchange ServerMicrosoft | 2000-sp3, 2003-sp2, 2007-sp1 | n/a |
Timeline
Publicly disclosed
Feb 10, 2009
Added to Industry KEV feed
Jun 20, 2017
Last updated
Apr 22, 2026
Weakness Type
- CWE-20 Improper Input Validation
References
- exploitVulnCheck exploitation report
- other51838
- otherMS09-003
- other33838
- otheroval:org.mitre.oval:def:6159
FAQ
Common Questions.
The Electronic Messaging System Microsoft Data Base (EMSMDB32) provider in Microsoft Exchange 2000 Server SP3 and Exchange Server 2003 SP2, as used in Exchange System Attendant, allows remote attackers to cause a denial of service (application outage) via a malformed MAPI command, aka "Literal Processing Vulnerability…
Affected: Exchange Server (Microsoft) versions 2000-sp3, 2003-sp2, 2007-sp1. The full list is in the CVE brief.
It is exploited in the wild, listed in Industry KEV feed since Jun 20, 2017.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.
Is CVE-2009-0099 On Your Attack Surface?
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