CVE-2004-0847

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2022-04-29. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Weaponized
9.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 74%
CISA-KEV: Not listedEPSS: 74%CVSS: 9.8Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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."

CVSS v3
9.8
EG Score
9.8(medium)
EPSS
99.4%
KEV
Not listed

Published

November 3, 2004

Last Modified

June 16, 2026

Advisory Details (5)

Auto-updated Jun 23, 2026
No patch confirmed yet. Sources: cert.
generic

IBM X-Force Exchange

https://exchange.xforce.ibmcloud.com/vulnerabilities/17644
generic

Microsoft Security Bulletin MS05-004 - Important | Microsoft Learn

https://docs.microsoft.com/en-us/security-updates/securitybulletins/2005/ms05-004
generic
http://www.securityfocus.com/bid/11342
cert

VU#283646 - Microsoft ASP.NET fails to perform proper canonicalization

http://www.kb.cert.org/vuls/id/283646
generic

GUSI / Discussion / Open Discussion

http://sourceforge.net/mailarchive/forum.php?thread_id=5671607&forum_id=24754

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 2× in last 7d / 8× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-20 17:02 UTCEPSS rescore
  2. 2026-07-19 14:25 UTCEPSS rescore
  3. 2026-07-13 06:07 UTCEPSS rescore
  4. 2026-07-04 06:26 UTCEPSS rescore
  5. 2026-06-28 14:02 UTCEPSS rescore
  6. 2026-06-28 04:52 UTCEPSS rescore
  7. 2026-06-27 03:04 UTCEPSS rescore
  8. 2026-06-23 21:29 UTCEPSS rescore
  9. 2026-06-21 01:56 UTCEPSS rescore
  10. 2026-06-17 17:49 UTCEPSS rescore
  11. 2026-06-17 17:49 UTCEPSS rescore
  12. 2026-06-16 17:49 UTCEPSS rescore
  13. 2026-06-16 17:49 UTCEPSS rescore
  14. 2026-06-15 17:43 UTCEPSS rescore
  15. 2026-06-12 23:08 UTCEPSS rescore
  16. 2026-06-11 13:55 UTCEPSS rescore
  17. 2026-06-10 22:13 UTCEPSS rescore
  18. 2026-06-08 14:13 UTCEPSS rescore
  19. 2026-06-06 13:44 UTCEPSS rescore
  20. 2026-06-06 13:44 UTCEPSS rescore
  21. 2026-06-06 13:44 UTCEPSS rescore
  22. 2026-06-05 22:43 UTCEPSS rescore
  23. 2026-06-05 22:43 UTCEPSS rescore
  24. 2026-06-04 13:09 UTCEPSS rescore
  25. 2026-06-02 20:10 UTCEPSS rescore
Show 29 more
  1. 2026-06-01 13:49 UTCEPSS rescore
  2. 2026-06-01 13:49 UTCEPSS rescore
  3. 2026-05-31 22:28 UTCEPSS rescore
  4. 2026-05-31 00:13 UTCEPSS rescore
  5. 2026-05-31 00:13 UTCEPSS rescore
  6. 2026-05-29 13:40 UTCEPSS rescore
  7. 2026-05-29 13:40 UTCEPSS rescore
  8. 2026-05-28 13:42 UTCEPSS rescore
  9. 2026-05-28 13:42 UTCEPSS rescore
  10. 2026-05-28 13:42 UTCEPSS rescore
  11. 2026-05-27 13:37 UTCEPSS rescore
  12. 2026-05-26 13:41 UTCEPSS rescore
  13. 2026-05-26 13:41 UTCEPSS rescore
  14. 2026-05-26 07:16 UTCEPSS rescore
  15. 2026-05-26 07:16 UTCEPSS rescore
  16. 2026-05-22 21:15 UTCEPSS rescore
  17. 2026-05-20 22:36 UTCEPSS rescore
  18. 2026-05-20 11:20 UTCEPSS rescore
  19. 2026-05-20 11:20 UTCEPSS rescore
  20. 2026-05-20 08:30 UTCGHSA enrichment
  21. 2026-05-20 04:05 UTCGHSA enrichment
  22. 2026-05-19 23:39 UTCGHSA enrichment
  23. 2026-05-19 19:14 UTCGHSA enrichment
  24. 2026-05-19 14:49 UTCGHSA enrichment
  25. 2026-05-19 06:31 UTCGHSA enrichment
  26. 2026-05-19 02:05 UTCEG score recompute
  27. 2026-05-19 02:05 UTCGHSA enrichment
  28. 2026-05-18 21:29 UTCEPSS rescore
  29. 2026-05-18 21:29 UTCEPSS rescore

Publicly available exploits

(1 reference)

Working exploit code is in the public domain (1 Exploit-DB entry). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • Exploit-DBEDB-24666✓ verified
    First seen Oct 6, 2004

    Microsoft ASP.NET 1.x - URI Canonicalization Unauthorized Web Access

    Open source ↗

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2004-0847?
CVE-2004-0847 is a critical vulnerability published on November 3, 2004. 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."
When was CVE-2004-0847 disclosed?
CVE-2004-0847 was first published in the National Vulnerability Database on November 3, 2004, with the most recent update on June 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2004-0847 actively exploited?
CVE-2004-0847 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2004-0847?
CVE-2004-0847 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2004-0847?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2004-0847, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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