CVE-2006-1540

CVE-2006-1540 is a critical-severity vulnerability in Microsoft Office with a CVSS 2.0 base score of 9.3. Its EPSS exploit-prediction score of 44% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-94.

Key facts

Description

MSO.DLL in Microsoft Office 2000, Office XP (2002), and Office 2003 allows user-assisted attackers to cause a denial of service and execute arbitrary code via multiple attack vectors, as originally demonstrated using a crafted document record with a malformed string, as demonstrated by replacing a certain "01 00 00 00" byte sequence with an "FF FF FF FF" byte sequence, possibly causing an invalid array index, in (1) an Excel .xls document, which triggers an access violation in ole32.dll; (2) an Excel .xlw document, which triggers an access violation in excel.exe; (3) a Word document, which triggers an access violation in mso.dll in winword.exe; and (4) a PowerPoint document, which triggers an access violation in powerpnt.txt. NOTE: after the initial disclosure, this issue was demonstrated by triggering an integer overflow using an inconsistent size for a Unicode "Sheet Name" string.

Frequently asked questions

What is CVE-2006-1540?
MSO.DLL in Microsoft Office 2000, Office XP (2002), and Office 2003 allows user-assisted attackers to cause a denial of service and execute arbitrary code via multiple attack vectors, as originally demonstrated using a crafted document record with a malformed string, as demonstrated by replacing a certain "01 00 00 00" byte sequence with an "FF FF FF FF" byte sequence, possibly causing an invalid array index, in (1) an Excel .xls document, which triggers an access violation in ole32.dll; (2) an Excel .xlw document, which triggers an access violation in excel.exe; (3) a Word document, which triggers an access violation in mso.dll in winword.exe; and (4) a PowerPoint document, which triggers an access violation in powerpnt.txt. NOTE: after the initial disclosure, this issue was demonstrated by triggering an integer overflow using an inconsistent size for a Unicode "Sheet Name" string.
How severe is CVE-2006-1540?
CVE-2006-1540 has a CVSS 2.0 base score of 9.3, rated critical severity.
Is CVE-2006-1540 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 44% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2006-1540?
CVE-2006-1540 primarily affects Microsoft Office. In total, 15 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2006-1540?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2006-1540 published?
CVE-2006-1540 was published on 2006-03-30 and last updated on 2026-06-16.

References

Affected products (15)

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