BugZero | Cisco BugID CSCvq05584 - Cisco IOS and IOS XE Software Tcl Arbitrary Code E...

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BugZero | Cisco BugID CSCvq05584 - Cisco IOS and IOS XE Software Tcl Arbitrary Code E...

ODD
Cisco
CSCvq05584

Cisco - Defect ID: CSCvq05584

Cisco IOS and IOS XE Software Tcl Arbitrary Code Execution Vulnerability

ODD
Cisco
CSCvq05584

Cisco - Defect ID: CSCvq05584

Cisco IOS and IOS XE Software Tcl Arbitrary Code Execution Vulnerability

Last updated on May 7th, 2026

BugZero Risk Score
9.7 High

Overall: 9.7

Severity: 10.0

Lifecycle: 9.1

Popularity: 7.8

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Bug Details

Description

Symptom

A vulnerability in the Tool Command Language (Tcl) interpreter of Cisco IOS Software and Cisco IOS XE Software could allow an authenticated, local attacker with privileged EXEC credentials to execute arbitrary code on the underlying operating system (OS) with root privileges. The vulnerability is due to insufficient input validation of data passed to the Tcl interpreter. An attacker could exploit this vulnerability by loading malicious Tcl code on an affected device. A successful exploit could allow the attacker to cause memory corruption or execute the code with root privileges on the underlying OS of the affected device. Cisco has released software updates that address this vulnerability. There are no workarounds that address this vulnerability. Cisco has published a security advisory containing additional details which is available at the following link: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-tcl-ace-C9KuVKmm

Conditions

For information on fixed versions of software consult the Cisco IOS Software checker: https://tools.cisco.com/security/center/softwarechecker.x See Vulnerable Products Section of the advisory for full details: https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-tcl-ace-C9KuVKmm

Workaround

There are no workarounds that address this vulnerability.

Further Problem Description

Please refer to the Security Advisory.

PSIRT Evaluation

The Cisco PSIRT has assigned this bug the following CVSS version 3 score. The Base CVSS score as of the time of evaluation is 6.7: https://tools.cisco.com/security/center/cvssCalculator.x?version=3.0&vector=CVSS:3.0/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H CVE ID CVE-2020-3204 has been assigned to document this issue. Additional information on Cisco''s security vulnerability policy can be found at the following URL: http://www.cisco.com/en/US/products/products_security_vulnerability_policy.html

Change history

2025-06-02 Added: 16.10.3, 16.12.1v, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1z1, 16.12.1z2, 16.12.2r, 16.12.2s, 16.12.2t, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.3.10, 16.3.11, 16.6.10, 16.6.8, 16.6.9, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8, 17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.2, 17.1.3, 17.2.1, 17.2.1LA, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.3.5a, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.1y, 17.6.2, 17.6.3, 17.6.3a, 17.7.1, 17.7.1a, 17.7.1b, 3.16.10aS_V155_3_S10A_FC8, 3.16.10bS_V155_3_S10B_FC2, 3.18.8aSP_V156_2_SP8A_FC2, 3.18.9SP_V156_2_SP9_FC3

Relevant Products

Click on a version to see all relevant bugs

Affected versions:No known affected versions

Fixed versions: 16.10.3, 16.12.1v, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1z1, 16.12.1z2, 16.12.2r, 16.12.2s, 16.12.2t, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.3.10, 16.3.11, 16.6.10, 16.6.8, 16.6.9, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8, 17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.2, 17.1.3, 17.2.1, 17.2.1LA, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.3.5a, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.1y, 17.6.2, 17.6.3, 17.6.3a, 17.7.1, 17.7.1a, 17.7.1b, 3.16.10aS_V155_3_S10A_FC8, 3.16.10bS_V155_3_S10B_FC2, 3.18.8aSP_V156_2_SP8A_FC2, 3.18.9SP_V156_2_SP9_FC3

Relevant Products

Click on a version to see all relevant bugs

Affected versions:No known affected versions

Fixed versions: 16.10.3, 16.12.1v, 16.12.1x, 16.12.1y, 16.12.1z, 16.12.1z1, 16.12.1z2, 16.12.2r, 16.12.2s, 16.12.2t, 16.12.3, 16.12.3a, 16.12.3s, 16.12.4, 16.12.4a, 16.12.5, 16.12.5a, 16.12.5b, 16.12.6, 16.12.6a, 16.12.7, 16.3.10, 16.3.11, 16.6.10, 16.6.8, 16.6.9, 16.9.5, 16.9.5f, 16.9.6, 16.9.7, 16.9.8, 17.1.1, 17.1.1a, 17.1.1s, 17.1.1t, 17.1.2, 17.1.3, 17.2.1, 17.2.1LA, 17.2.1a, 17.2.1r, 17.2.1v, 17.2.2, 17.2.3, 17.3.1, 17.3.1a, 17.3.1w, 17.3.1x, 17.3.1z, 17.3.2, 17.3.2a, 17.3.3, 17.3.3a, 17.3.4, 17.3.4a, 17.3.4b, 17.3.4c, 17.3.5, 17.3.5a, 17.4.1, 17.4.1a, 17.4.1b, 17.4.1c, 17.4.2, 17.4.2a, 17.5.1, 17.5.1a, 17.6.1, 17.6.1a, 17.6.1w, 17.6.1x, 17.6.1y, 17.6.2, 17.6.3, 17.6.3a, 17.7.1, 17.7.1a, 17.7.1b, 3.16.10aS_V155_3_S10A_FC8, 3.16.10bS_V155_3_S10B_FC2, 3.18.8aSP_V156_2_SP8A_FC2, 3.18.9SP_V156_2_SP9_FC3

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