How severe is CVE-2001-0669?

CVE-2001-0669 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-2001-0669 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2001-0669?

CVE-2001-0669 primarily affects Cisco Catalyst 6000 Intrusion Detection System Module. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2001-0669?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2001-0669 published?

CVE-2001-0669 was published on 2001-10-30 and last updated on 2026-06-16.

CVE-2001-0669

CVE-2001-0669 is a high-severity vulnerability in Cisco Catalyst 6000 Intrusion Detection System Module with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Cisco Catalyst 6000 Intrusion Detection System Module
Published: 2001-10-30
Last modified: 2026-06-16

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.

Frequently asked questions

What is CVE-2001-0669?: 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.
How severe is CVE-2001-0669?: CVE-2001-0669 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2001-0669 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2001-0669?: CVE-2001-0669 primarily affects Cisco Catalyst 6000 Intrusion Detection System Module. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2001-0669?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2001-0669 published?: CVE-2001-0669 was published on 2001-10-30 and last updated on 2026-06-16.

References

Affected products (8)

cpe:2.3:a:cisco:catalyst_6000_intrusion_detection_system_module:*:*:*:*:*:*:*:*
cpe:2.3:a:cisco:secure_intrusion_detection_system:*:*:*:*:*:*:*:*
cpe:2.3:a:iss:realsecure_network_sensor:5.x:*:*:*:*:*:*:*
cpe:2.3:a:iss:realsecure_network_sensor:6.x:*:*:*:*:*:*:*
cpe:2.3:a:iss:realsecure_server_sensor:5.5:*:*:*:*:*:*:*
cpe:2.3:a:iss:realsecure_server_sensor:6.0:*:*:*:*:*:*:*
cpe:2.3:a:snort:snort:1.8.1:*:*:*:*:*:*:*
cpe:2.3:h:enterasys:dragon:4.x:*:*:*:*:*:*:*