CVE-2009-0133

CVE-2009-0133 is a critical-severity vulnerability in Microsoft Html Help Workshop with a CVSS 2.0 base score of 10.0. Its EPSS exploit-prediction score of 67% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-119.

Key facts

Description

Buffer overflow in Microsoft HTML Help Workshop 4.74 and earlier allows context-dependent attackers to execute arbitrary code via a .hhp file with a long "Index file" field, possibly a related issue to CVE-2006-0564.

Frequently asked questions

What is CVE-2009-0133?
Buffer overflow in Microsoft HTML Help Workshop 4.74 and earlier allows context-dependent attackers to execute arbitrary code via a .hhp file with a long "Index file" field, possibly a related issue to CVE-2006-0564.
How severe is CVE-2009-0133?
CVE-2009-0133 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-2009-0133 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 67% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-0133?
CVE-2009-0133 affects Microsoft Html Help Workshop. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2009-0133?
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-2009-0133 published?
CVE-2009-0133 was published on 2009-01-15 and last updated on 2026-06-16.

References

Affected products (1)

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