CVE-2009-1123: Microsoft Windows Improper Input Validation Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on , 4,649 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 4.9%
EPSS score, percentile 92 of all scored records
- How severe?
- 7.8 High
CVSS v3.1 base score, from CISA's enrichment of the record
- What should I do?
CISA deadline . Apply updates per vendor instructions.
- Which versions are affected?
Not stated. The CVE record gives vendor and product as “n/a” and the version as “unspecified”.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: .
Advisories and patches
Linked from CISA's catalog entry
Affected products and versions
The CVE record does not name affected products or versions: vendor and product are “n/a” and the version is “unspecified”.
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
About this vulnerability
The kernel in Microsoft Windows does not properly validate changes to unspecified kernel objects, which allows local users to gain privileges via a crafted application.
Summary: CISA's KEV catalog, as of .
- CISA added CVE-2009-1123 to its Known Exploited Vulnerabilities (KEV) catalog on 3 Mar 2022.
- CISA's ransomware flag for this entry is "Unknown": no evidence of ransomware use in the catalog, which is not proof of none.
- The due date CISA sets for the required action is 24 Mar 2022.
- The CVE record was published on 10 Jun 2009, 4,649 days before it was added to KEV.
- The CVE record carries a CVSS v3.1 base score of 7.8 (High), taken from CISA's enrichment of the record.
- FIRST's EPSS model puts the probability of exploitation in the next 30 days at 4.9% (percentile 92), as of 28 Oct 2026.
- CISA's SSVC assessment in the CVE record: exploitation active, automatable no, technical impact total.
Source: CISA Known Exploited Vulnerabilities (KEV) catalog, 2026.10.28, as of ; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of ; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of . About the data.
Description
The kernel in Microsoft Windows 2000 SP4, XP SP2 and SP3, Server 2003 SP2, Vista Gold, SP1, and SP2, and Server 2008 SP2 does not properly validate changes to unspecified kernel objects, which allows local users to gain privileges via a crafted application, aka "Windows Kernel Desktop Vulnerability."
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of . About the data.
Weakness
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| CVE record published | |
| Added to CISA KEV | |
| CISA due date for the required action | |
| CVE record last updated |
References
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