CVE-2009-0557: Microsoft Office Object Record Corruption Vulnerability
- Is it exploited?
Yes. CISA added it to the Known Exploited Vulnerabilities catalog on 8 Jun 2022, 4,746 days after the CVE record was published.
- How likely is exploitation in the next 30 days?
- 52.8%
EPSS score, percentile 99 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 22 Jun 2022. 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 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
What to do
Required action, set by CISA
Apply updates per vendor instructions.
CISA due date for this action: 22 June 2022.
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 28 Oct 2026. About the data.
About this vulnerability
Microsoft Office contains an object record corruption vulnerability that allows remote attackers to execute code via a crafted Excel file with a malformed record object.
Summary: CISA's KEV catalog, as of 28 Oct 2026.
- CISA added CVE-2009-0557 to its Known Exploited Vulnerabilities (KEV) catalog on 8 Jun 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 22 Jun 2022.
- The CVE record was published on 10 Jun 2009, 4,746 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 52.8% (percentile 99), 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 28 Oct 2026; CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026; FIRST Exploit Prediction Scoring System (EPSS), v2026.06.15, as of 28 Oct 2026. About the data.
Description
Excel in Microsoft Office 2000 SP3, Office XP SP3, Office 2003 SP3, and Office 2004 and 2008 for Mac; Excel in 2007 Microsoft Office System SP1 and SP2; Open XML File Format Converter for Mac; Microsoft Office Excel Viewer 2003 SP3; Microsoft Office Excel Viewer; and Microsoft Office Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1 and SP2 allow remote attackers to execute arbitrary code via a crafted Excel file with a malformed record object, aka "Object Record Corruption Vulnerability."
Source: CVE List V5 (CVE Program), cve_2026-10-28_0000Z, as of 28 Oct 2026. About the data.
Weakness
- CWE-94: Improper Control of Generation of Code ('Code Injection')
CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record and the KEV entry.
Timeline
| Date | Event |
|---|---|
| 10 Jun 2009 | CVE record published |
| 8 Jun 2022 | Added to CISA KEV |
| 22 Jun 2022 | CISA due date for the required action |
| 22 Oct 2025 | CVE record last updated |
References
More exploited Microsoft vulnerabilities
- CVE-2026-96951: Microsoft Windows Command Injection Vulnerability
- CVE-2026-65660: Microsoft SharePoint Code Injection Vulnerability
- CVE-2026-81963: Microsoft Windows Link Following Vulnerability
- CVE-2026-85880: Microsoft Windows Heap-Based Buffer Overflow Vulnerability
- CVE-2019-1068: Microsoft SQL Server Remote Code Execution Vulnerability
- CVE-2026-33824: Microsoft Internet Key Exchange (IKE) Service Extensions Double Free Vulnerability