Is CVE-2004-0551 being actively exploited?

CVE-2004-0551 is not currently listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

What is the CVSS score for CVE-2004-0551?

CVE-2004-0551 has a CVSS 2.0 base score of 5.0 (MEDIUM).

CVE-2004-0551

MEDIUM · CVSS 5.0EPSS 3.1%EU EUVD

Cisco CatOS 5.x before 5.5(20) through 8.x before 8.2(2) and 8.3(2)GLX, as used in Catalyst switches, allows remote attackers to cause a denial of service (system crash and reload) by sending invalid packets instead of the final ACK portion of the three-way handshake to the (1) Telnet, (2) HTTP, or (3) SSH services, aka "TCP-ACK DoS attack."

Key facts

CVSS score: 5.0 (v2.0)
Severity: MEDIUM
CVSS vector: AV:N/AC:L/Au:N/C:N/I:N/A:P
EPSS score: 3.1% (88th percentile)
In CISA KEV: No
In EU EUVD: Yes (EUVD-2004-0550)
Published: August 6, 2004
NVD last modified: June 16, 2026
Status: Modified

EU Vulnerability Database (EUVD)

This vulnerability is also tracked by ENISA as EUVD-2004-0550 in the EU Vulnerability Database. Last updated in EUVD on August 8, 2024.

View on the EU Vulnerability Database

Affected products

cisco / catalyst 2901
cisco / catalyst 2902
cisco / catalyst 2926
cisco / catalyst 2926f
cisco / catalyst 2926gl
cisco / catalyst 2926gs
cisco / catalyst 2926t
cisco / catalyst 2948
cisco / catalyst 2948-ge-tx
cisco / catalyst 2948g-l3
cisco / catalyst 2980g
cisco / catalyst 2980g-a
cisco / catalyst 4000
cisco / catalyst 4500
cisco / catalyst 4503
cisco / catalyst 4506
cisco / catalyst 4507r
cisco / catalyst 4510r
cisco / catalyst 4912g
cisco / catalyst 5000
cisco / catalyst 6000 ws-svc-nam-1
cisco / catalyst 6000 ws-svc-nam-1
cisco / catalyst 6000 ws-svc-nam-2
cisco / catalyst 6000 ws-svc-nam-2
cisco / catalyst 6000 ws-x6380-nam
cisco / catalyst 6000 ws-x6380-nam
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos
cisco / catos

and 188 more…

Certified products that may be affected

4 FIPS 140 or Common Criteria certified products, from automated matching by sec-certs.org.

Cisco Catalyst 4506-E with Supervisor Card (WS-X45-SUP8-E) and Line Cards (WS-X4748-RJ45-E and WS-X4748-RJ45V+E) - Cisco Systems, Inc. - FIPS 140 2771 - historical
Cisco Catalyst 4506-E with Supervisor Cards (WS-X45-SUP7-E and WS-X45-Sup7L-E) and Line Cards (WS-X4748-RJ45-E and WS-X4748-RJ45V+E) - Cisco Systems, Inc. - FIPS 140 2748 - historical
Cisco Catalyst 4503-E, Catalyst 4506-E, Catalyst 4507R-E, Catalyst 4507R+E, Catalyst 4510R-E, Catalyst 4510R+E, Catalyst C4500X-16SFP+, Catalyst C4500X-F-16SFP+, Catalyst C4500X-32SFP+, Catalyst C4500X-F-32SFP+, Catalyst C4500X-24X-ES, Catalyst C4500X-40X-ES, Catalyst C4500X-24X-IPB with Supervisor Cards (WS-X45-SUP7-E, WS-X45-Sup7L-E) and Line Cards (WS-X4640-CSFP-E, WS-X4712-SFP+E, WS-X4748-NGPOE+E, WS-X4748-RJ45-E and WS-X4748-RJ45V+E) - Cisco Systems, Inc. - FIPS 140 2116 - historical
Cisco Catalyst 4503-E, Catalyst 4506-E, Catalyst 4507R-E, Catalyst 4507R+E, Catalyst 4510R-E, Catalyst 4510R+E with Supervisor Cards (WS-X45-SUP7-E and WS-X45-Sup7L-E) and Line Cards (WS-X4748-RJ45V+E, WS-X4712-SFP+E, WS-X4640-CSFP-E, WS-X4748-NGPOE+E, and WS-X4748-RJ45-E) - Cisco Systems, Inc. - FIPS 140 1982 - historical

References

http://www.cisco.com/warp/public/707/cisco-sa-20040609-catos.shtml
http://www.kb.cert.org/vuls/id/245190(Third Party Advisory, US Government Resource)
https://exchange.xforce.ibmcloud.com/vulnerabilities/16370

Last updated September 17, 2026 · Source: NVD, CISA KEV, FIRST.org EPSS

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