CVE-2008-0116: Microsoft Excel Rich Text Validation Flaw Allows Code Execution

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 20 September 2026. Confidence: high.

high priorityCVSS 9.3 and a 98.8th percentile EPSS score indicate severe impact and high predicted exploitation, though the flaw requires user-assisted file opening and a patch has long been available.

What it is

Microsoft Excel 2000 SP3 through 2003 SP2, Excel Viewer 2003, the Office Compatibility Pack, and Office 2004/2008 for Mac fail to properly validate rich text tags in spreadsheet content. A malformed file can trigger memory corruption that lets an attacker run arbitrary code in the context of the user who opens it.

Impact

Successful exploitation gives the attacker the same privileges as the logged-on user, allowing arbitrary code execution, data theft, or further compromise of the host. Because the flaw is in a widely deployed document format, a single crafted file can be reused across many targets.

Attack surface

Reached remotely by delivering a malformed Excel file (AV:N) that the victim must open, so exploitation requires user interaction (AC:M) but no authentication (Au:N). The attack vector is the rich text parsing path in Excel and related viewers/converters.

Exploitation

The record is not listed in CISA KEV and no ransomware use is documented, but EPSS is high at 0.482 (98.8th percentile), indicating substantial predicted exploitation activity. Reference tags include Patch and Vendor Advisory, confirming a fix exists.

What to do

• Apply Microsoft security bulletin MS08-014 (the vendor patch) to all affected Excel, Viewer, Compatibility Pack, and Mac Office installations.
• Block or strip untrusted Excel attachments at the email and web gateway, and disable automatic opening of Office documents from external sources.
• Use Microsoft Office file blocking / trusted location policies to prevent legacy .xls files from untrusted origins from being opened.
• Where legacy Excel is not required, migrate to a supported Office version that is not affected by this flaw.
• Educate users not to open unexpected spreadsheets, since exploitation depends on the victim opening the file.

Detection

• Hunt for Excel processes (EXCEL.EXE, viewers, converters) spawning child processes such as cmd.exe, powershell.exe, or wscript.exe.
• Monitor for Office applications loading or writing files in unusual locations (temp, startup, user profile) after opening a spreadsheet.
• Alert on crash or exception telemetry from Excel/Office components correlating with recently opened .xls files from email or downloads.
• Search endpoint logs for known exploit artifacts or malformed rich text structures in received Excel attachments.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.