CVE-2020-3204: Cisco IOS and IOS XE Software Tcl Arbitrary Code Execution Vulnerability

Severity: medium (CVSS 6.7 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2020-06-03 · updated 2026-06-17
Weakness: CWE-20

Description

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.

Affected products

Cisco IOS: 12.2(6)i1, 12.2(33)sre, 12.2(33)sre0a, 12.2(33)sre1, 12.2(33)sre2, 12.2(33)sre3 (+952)
Cisco IOS XE: 3.2.0se, 3.2.0sg, 3.2.1se, 3.2.1sg, 3.2.2se, 3.2.2sg (+319)

References

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