CVE-2004-0551
Cisco CatOS 5.x before 5.5(20) through 8.x before 8.2(2) and 8.3(2)GLX, as used in Catalyst...
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."
Exploit likelihood
What each source reports
NVD Score used
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."
- Record
CVE-2004-0551- CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Updated
- 2026-11-02
CVE List No score
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."
- Record
CVE-2004-0551- Updated
- 2026-11-02
EUVDEUVD-2004-0550 No score
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."
- Record
EUVD-2004-0550- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-cq5p-fgmw-rvxv No score
Cisco CatOS 5.x before 5.5(20) through 8.x before 8.2(2) and 8.3(2)GLX, as used in Catalyst...
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."
- Record
GHSA-cq5p-fgmw-rvxv- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2004-0551 is a medium vulnerability (CVSS 5.0) in Cisco Catos, published June 15, 2004. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 3.13%, the 87th percentile. No source names a fixed version.