CVE-2009-1535
HighPublic exploitThe 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…
Published Jun 10, 2009 · Updated Apr 22, 2026
Key Facts
Patch immediately- CVE-2009-1535 is a high-severity vulnerability (CVSS 7.5 v2) affecting Internet Information Services (Microsoft).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 98% probability of exploitation in the next 30 days.
- No fixed version is listed yet; check the vendor advisory for mitigations.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v2
7.5
AV:N/AC:L/Au:N/C:P/I:P/A:P
EPSS (30-day exploit likelihood)
98%
Higher than 99.9% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
Available
Proof-of-concept or weaponized module
Get the full CVE-2009-1535 brief as a PDF
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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.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Internet Information ServicesMicrosoft | 5.1, 6.0 | n/a |
Timeline
Publicly disclosed
Jun 10, 2009
Last updated
Apr 22, 2026
Weakness Type
- CWE-287 Improper Authentication
References
- advisoryhttp://blog.zoller.lu/2009/05/iis-6-webdac-auth-bypass-and-data.html
- advisoryhttp://isc.sans.org/diary.html?n&storyid=6397
- advisoryoval:org.mitre.oval:def:6029
- advisory20090616 IIS WebDav Vulnerability CVE ID
- advisoryTA09-160A
FAQ
Common Questions.
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 "/pr…
Affected: Internet Information Services (Microsoft) versions 5.1, 6.0. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
Public exploit code is available.
No fixed version is listed yet; check the vendor advisory for mitigations.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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