Skip to content
Fencer Vulns
critical 9.8

CVE-2004-0847 in the critical feed json

The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restrict…

published 2004-10-06 22 y ago modified 2026-06-16 4 mo ago also EUVD-2004-0845

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
75.7%
EPSS 75.7% chance of exploitation in 30 days, percentile 99.5%
public exploits
1
Exploit-DB

Summary

The Microsoft .NET forms authentication capability for ASP.NET allows remote attackers to bypass authentication for .aspx files in restricted directories via a request containing a (1) "\" (backslash) or (2) "%5C" (encoded backslash), aka "Path Validation Vulnerability."

Timeline

  1. First public exploit (EDB-24666)
  2. Published

Exploit prediction

75.70% chance of exploitation in the next 30 days, higher than 99.5% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • EDB-24666 Microsoft ASP.NET 1.x - URI Canonicalization Unauthorized Web Access webapps, 2004-10-06
  • archives.neohapsis.com http://archives.neohapsis.com/archives/ntbugtraq/2004-q3/0221.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.