Cisco IOS up to 12.0(3) Telnet TCP Connection denial of service

CVSS Meta Temp Score
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CTI Interest Score
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6.1$0-$5k0.00

Summaryinfo

A vulnerability classified as critical was found in Cisco IOS up to 12.0(3). This impacts an unknown function of the component Telnet TCP Connection Handler. Such manipulation leads to denial of service. This vulnerability is uniquely identified as CVE-2004-1464. The attack can be launched remotely. Moreover, an exploit is present. Restrictive firewalling should be applied.

Detailsinfo

A vulnerability, which was classified as critical, has been found in Cisco IOS up to 12.0(3) (Router Operating System). Affected by this issue is an unknown function of the component Telnet TCP Connection Handler. The manipulation with an unknown input leads to a denial of service vulnerability. Using CWE to declare the problem leads to CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. Impacted is confidentiality, and integrity. CVE summarizes:

Cisco IOS 12.2(15) and earlier allows remote attackers to cause a denial of service (refused VTY (virtual terminal) connections), via a crafted TCP connection to the Telnet or reverse Telnet port.

The bug was discovered 08/27/2004. The weakness was disclosed 08/27/2004 with Cisco (Website). The advisory is shared for download at cisco.com. This vulnerability is handled as CVE-2004-1464 since 02/13/2005. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are unknown but a public exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

After immediately, there has been an exploit disclosed. It is declared as attacked. As 0-day the estimated underground price was around $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 15627 (Cisco IOS Telnet Service DoS (CSCef46191)), which helps to determine the existence of the flaw in a target environment. It is assigned to the family CISCO, running in the context l and relying on port 161. The commercial vulnerability scanner Qualys is able to test this issue with plugin 38308 (Cisco IOS Telnet Service Remote Denial of Service Vulnerability). This issue was added on 05/19/2023 to the CISA Known Exploited Vulnerabilities Catalog with a due date of 06/09/2023:

Apply updates per vendor instructions.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at cisco.com.Addressing this vulnerability is possible by firewalling . The best possible mitigation is suggested to be applying a restrictive firewalling. A possible mitigation has been published immediately after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at X-Force (17131), Tenable (15627), EUVD (EUVD-2004-1458), SecurityFocus (BID 11060†) and OSVDB (9265†). ciac.org is providing further details. Once again VulDB remains the best source for vulnerability data.

Productinfo

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Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.2
VulDB Meta Temp Score: 6.1

VulDB Base Score: 6.5
VulDB Temp Score: 6.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 5.9
NVD Vector: 🔍

CVSSv2info

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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Denial of service
CWE: CWE-404
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Access: Public
Status: Attacked

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Current Price Estimation: 🔍

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Nessus ID: 15627
Nessus Name: Cisco IOS Telnet Service DoS (CSCef46191)
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍
Nessus Port: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Countermeasuresinfo

Recommended: Firewall
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍
Exploit Delay Time: 🔍

Patch: cisco.com

Timelineinfo

08/27/2004 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/27/2004 +0 days 🔍
08/30/2004 +2 days 🔍
11/04/2004 +66 days 🔍
11/08/2004 +4 days 🔍
12/31/2004 +53 days 🔍
02/13/2005 +44 days 🔍
10/21/2025 +7555 days 🔍

Sourcesinfo

Vendor: cisco.com

Advisory: cisco.com
Researcher: http://www.cisco.com
Organization: Cisco
Status: Confirmed

CVE: CVE-2004-1464 (🔍)
GCVE (CVE): GCVE-0-2004-1464
GCVE (VulDB): GCVE-100-812
EUVD: 🔍

OVAL: 🔍

CERT: 🔍
X-Force: 17131 - Cisco IOS Telnet denial of service, Medium Risk
SecurityFocus: 11060 - Cisco IOS Telnet Service Remote Denial of Service Vulnerability
Secunia: 12395 - Cisco IOS Telnet Service Denial of Service Vulnerability, Less Critical
OSVDB: 9265 - Cisco IOS Telnet Service DoS
SecurityTracker: 1011079
SecuriTeam: securiteam.com
Vulnerability Center: 5745 - [cisco-sa-20040827-telnet] DoS in Cisco IOS via Telnet, Medium

scip Labs: https://www.scip.ch/en/?labs.20161013
Misc.: 🔍

Entryinfo

Created: 08/30/2004 11:45
Updated: 10/21/2025 22:01
Changes: 08/30/2004 11:45 (99), 06/29/2019 09:50 (2), 04/28/2024 16:58 (30), 06/28/2024 02:00 (11), 09/09/2024 22:30 (3), 11/21/2024 14:10 (3), 07/06/2025 18:46 (2), 07/30/2025 06:10 (1), 10/21/2025 22:01 (1)
Complete: 🔍
Cache ID: 216:A1E:103

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