CVE-2009-1535

CVE-2009-1535 is a high-severity vulnerability in Microsoft Internet Information Services with a CVSS 2.0 base score of 7.5. Its EPSS exploit-prediction score of 98% places it in the 100th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-287.

Key facts

Description

The WebDAV extension in Microsoft Internet Information Services (IIS) 5.1 and 6.0 allows remote attackers to bypass URI-based protection mechanisms, and list folders or read, create, or modify files, via a %c0%af (Unicode / character) at an arbitrary position in the URI, as demonstrated by inserting %c0%af into a "/protected/" initial pathname component to bypass the password protection on the protected\ folder, aka "IIS 5.1 and 6.0 WebDAV Authentication Bypass Vulnerability," a different vulnerability than CVE-2009-1122.

Frequently asked questions

What is CVE-2009-1535?
The WebDAV extension in Microsoft Internet Information Services (IIS) 5.1 and 6.0 allows remote attackers to bypass URI-based protection mechanisms, and list folders or read, create, or modify files, via a %c0%af (Unicode / character) at an arbitrary position in the URI, as demonstrated by inserting %c0%af into a "/protected/" initial pathname component to bypass the password protection on the protected\ folder, aka "IIS 5.1 and 6.0 WebDAV Authentication Bypass Vulnerability," a different vulnerability than CVE-2009-1122.
How severe is CVE-2009-1535?
CVE-2009-1535 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2009-1535 being actively exploited?
It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 98% (100th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-1535?
CVE-2009-1535 primarily affects Microsoft Internet Information Services. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-1535?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2009-1535 published?
CVE-2009-1535 was published on 2009-06-10 and last updated on 2026-06-16.

References

Affected products (2)

More vulnerabilities in Microsoft Internet Information Services

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Other CWE-287 (Improper Authentication) vulnerabilities

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Threat intelligence

Threat-intel indicators referencing this CVE: