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 den
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."
- Published
- Aug 6, 2004
- Updated
- Jun 16, 2026
- EPSS
- 3.1% · 87th percentile
- CWE
- —
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Report tools
Action score
21
Monitor
Low priority for now.
- CVSS
- 20 / 40 · 5.0 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 1 / 30 · 3.1%
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpAffected systems
| Vendor | Product | CPE |
|---|---|---|
| cisco | catos | cpe:2.3:o:cisco:catos |
| cisco | catalyst 2901 | cpe:2.3:h:cisco:catalyst_2901 |
| cisco | catalyst 2902 | cpe:2.3:h:cisco:catalyst_2902 |
| cisco | catalyst 2926 | cpe:2.3:h:cisco:catalyst_2926 |
| cisco | catalyst 2926f | cpe:2.3:h:cisco:catalyst_2926f |
| cisco | catalyst 2926gl | cpe:2.3:h:cisco:catalyst_2926gl |
| cisco | catalyst 2926gs | cpe:2.3:h:cisco:catalyst_2926gs |
| cisco | catalyst 2926t | cpe:2.3:h:cisco:catalyst_2926t |
| cisco | catalyst 2948 | cpe:2.3:h:cisco:catalyst_2948 |
| cisco | catalyst 2948-ge-tx | cpe:2.3:h:cisco:catalyst_2948-ge-tx |
| cisco | catalyst 2948g-l3 | cpe:2.3:h:cisco:catalyst_2948g-l3 |
| cisco | catalyst 2980g | cpe:2.3:h:cisco:catalyst_2980g |
and 12 more
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- cisco catalyst 2901all versions
- cisco catalyst 2902all versions
- cisco catalyst 2926all versions
- cisco catalyst 2926fall versions
- cisco catalyst 2926glall versions
- cisco catalyst 2926gsall versions
- cisco catalyst 2926tall versions
- cisco catalyst 2948all versions
- cisco catalyst 2948-ge-txall versions
- cisco catalyst 2948g-l3all versions
- cisco catalyst 2980gall versions
- cisco catalyst 2980g-aall versions
- cisco catalyst 4000all versions
- cisco catalyst 4500all versions
- cisco catalyst 4503all versions
- cisco catalyst 4506all versions
- cisco catalyst 4507rall versions
- cisco catalyst 4510rall versions
- cisco catalyst 4912gall versions
- cisco catalyst 5000all versions
Same product
cisco: all recordsOther highest-scoring records for the same primary product.
- CVE-2003-0216Unknown vulnerability in Cisco Catalyst 7.5(1) allows local users to bypass authentication and gain access to the enable mode without a pass38Monitor
- CVE-2001-0041Memory leak in Cisco Catalyst 4000, 5000, and 6000 series switches allows remote attackers to cause a denial of service via a series of fail35Monitor
- CVE-2002-1222Buffer overflow in the embedded HTTP server for Cisco Catalyst switches running CatOS 5.4 through 7.3 allows remote attackers to cause a den31Monitor
- CVE-2008-4963Unspecified vulnerability in the VLAN Trunking Protocol (VTP) implementation on Cisco IOS and CatOS, when the VTP operating mode is not tran29Monitor
- CVE-2007-5651Unspecified vulnerability in the Extensible Authentication Protocol (EAP) implementation in Cisco IOS 12.3 and 12.4 on Cisco Access Points a29Monitor
- CVE-2002-2316Cisco Catalyst 4000 series switches running CatOS 5.5.5, 6.3.5, and 7.1.2 do not always learn MAC addresses from a single initial packet, wh20Monitor
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
No known public exploit
No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
No dated events beyond publication.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- none
- Integrity
- none
- Availability
- P · the service can be disrupted
- Attack complexity
- Low
- Confidentiality impact
- None
- Integrity impact
- None
- Availability impact
- P
Weakness class (CWE)
—
CVSS vector
AV:N/AC:L/Au:N/C:N/I:N/A:P
nvd-primary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
MITRE has no CAPEC/ATT&CK mapping for this CWE.
Change log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- www.cisco.com/warp/public/707/cisco-sa-20040609-catos.shtml
- www.kb.cert.org/vuls/id/245190
- exchange.xforce.ibmcloud.com/vulnerabilities/16370
Vendor advisories and official records. Exploit/PoC links are deliberately left out.