CVE-2000-0457
HighPublic exploitISM.DLL in IIS 4.0 and 5.0 allows remote attackers to read file contents by requesting the file and appending a large number of encoded spaces (%20) and terminated with a .htr extension, aka the ".HTR File Fragment Reading" or "File Fragment Reading via .HTR" vulnerability.
Published May 11, 2000 · Updated Apr 15, 2026
Key Facts
Patch immediately- CVE-2000-0457 is a high-severity vulnerability (CVSS 7.5 v2) affecting Internet Information Server (Microsoft), Internet Information Services (Microsoft).
- It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
- EPSS estimates a 53% 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)
53%
Higher than 98.9% 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-2000-0457 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
Description
ISM.DLL in IIS 4.0 and 5.0 allows remote attackers to read file contents by requesting the file and appending a large number of encoded spaces (%20) and terminated with a .htr extension, aka the ".HTR File Fragment Reading" or "File Fragment Reading via .HTR" vulnerability.
Affected Products
2 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Internet Information ServerMicrosoft | 4.0 | n/a |
| Internet Information ServicesMicrosoft | 5.0 | n/a |
Timeline
Publicly disclosed
May 11, 2000
Last updated
Apr 15, 2026
References
- exploitExploitDB-19908
- other20000511 Alert: IIS ism.dll exposes file contents
- otherMS00-031
- otheriis-ism-file-access(4448)
- other1193
FAQ
Common Questions.
ISM.DLL in IIS 4.0 and 5.0 allows remote attackers to read file contents by requesting the file and appending a large number of encoded spaces (%20) and terminated with a .htr extension, aka the ".HTR File Fragment Reading" or "File Fragment Reading via .HTR" vulnerability.
Affected: Internet Information Server (Microsoft) versions 4.0; 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.
Is CVE-2000-0457 Running On Your Attack Surface?
Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.
Request A Demo