CVE-2001-0669

Name: CVE-2001-0669
Creator: NVD / NIST
Published: 2001-10-30T05:00:00+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

UnknownEPSS 4.39%

Last modified Jun 16, 2026

CVE-2001-0669 is a vulnerability of currently unknown severity. Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Catalyst 6000 Intrusion Detection System Module, (3) Dragon Sensor 4.x, (4) Snort before 1.8.1, (5) ISS RealSecure Network Sensor 5.x and 6.x before XPU 3.2, and (6) ISS RealSecure Server Sensor 5.5 and 6.0 for Windows, allow remote attackers to evade detection of HTTP attacks via non-standard "%u" Unicode encoding of ASCII characters in the requested URL.. EPSS estimates a 4.39% chance of exploitation in the next 30 days.

Description

Various Intrusion Detection Systems (IDS) including (1) Cisco Secure Intrusion Detection System, (2) Cisco Catalyst 6000 Intrusion Detection System Module, (3) Dragon Sensor 4.x, (4) Snort before 1.8.1, (5) ISS RealSecure Network Sensor 5.x and 6.x before XPU 3.2, and (6) ISS RealSecure Server Sensor 5.5 and 6.0 for Windows, allow remote attackers to evade detection of HTTP attacks via non-standard "%u" Unicode encoding of ASCII characters in the requested URL.

Metrics

EPSS Probability

4.39%

90.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Vendor	Product	Versions
Cisco	Catalyst 6000 Intrusion Detection System Module	All versions
Cisco	Secure Intrusion Detection System	All versions
Iss	Realsecure Network Sensor	5.x
Iss	Realsecure Network Sensor	6.x
Iss	Realsecure Server Sensor	5.5
Iss	Realsecure Server Sensor	6.0
Snort	Snort	1.8.1
Enterasys	Dragon	4.x

References

http://marc.info/?l=bugtraq&m=99972950200602&w=2
http://www.cisco.com/warp/public/707/cisco-intrusion-detection-obfuscation-vuln-pub.shtmlPatch, Vendor Advisory
http://www.kb.cert.org/vuls/id/548515US Government Resource
http://www.securityfocus.com/bid/3292
http://xforce.iss.net/alerts/advise95.phpPatch, Vendor Advisory
http://marc.info/?l=bugtraq&m=99972950200602&w=2
http://www.cisco.com/warp/public/707/cisco-intrusion-detection-obfuscation-vuln-pub.shtmlPatch, Vendor Advisory
http://www.kb.cert.org/vuls/id/548515US Government Resource
http://www.securityfocus.com/bid/3292
http://xforce.iss.net/alerts/advise95.phpPatch, Vendor Advisory

Timeline

Published: Oct 30, 2001
Last Modified: Jun 16, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2001-0669?

How severe is CVE-2001-0669?

Severity scoring for CVE-2001-0669 is pending analysis. The EPSS model estimates a 4.39% probability of exploitation in the next 30 days.

How do I fix CVE-2001-0669?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2001-0669?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST