CVE-2009-1122
HighPublic exploitThe WebDAV extension in Microsoft Internet Information Services (IIS) 5.0 on Windows 2000 SP4 does not properly decode URLs, which allows remote attackers to bypass authentication, and possibly read or create files, via a crafted HTTP request, aka "IIS 5.0 WebDAV Authentication…
Published Jun 10, 2009 · Updated Apr 22, 2026
Key Facts
Patch immediately- CVE-2009-1122 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-2009-1122 brief as a PDF
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Description
The WebDAV extension in Microsoft Internet Information Services (IIS) 5.0 on Windows 2000 SP4 does not properly decode URLs, which allows remote attackers to bypass authentication, and possibly read or create files, via a crafted HTTP request, aka "IIS 5.0 WebDAV Authentication Bypass Vulnerability," a different vulnerability than CVE-2009-1535.
Affected Products
1 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Internet Information ServicesMicrosoft | 5.0 | n/a |
Timeline
Publicly disclosed
Jun 10, 2009
Last updated
Apr 22, 2026
Weakness Type
- CWE-287 Improper Authentication
References
- advisoryoval:org.mitre.oval:def:5861
- advisory20090616 IIS WebDav Vulnerability CVE ID
- advisory35232
- advisory1022358
- advisoryTA09-160A
FAQ
Common Questions.
The WebDAV extension in Microsoft Internet Information Services (IIS) 5.0 on Windows 2000 SP4 does not properly decode URLs, which allows remote attackers to bypass authentication, and possibly read or create files, via a crafted HTTP request, aka "IIS 5.0 WebDAV Authentication Bypass Vulnerability," a different vulne…
Affected: Internet Information Services (Microsoft) versions 5.0. 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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