CVE intelligence and bounded remediation

CVE-2022-20676 — Cisco Ios Xe security vulnerability

High CVSS 7.2

A vulnerability in the Tool Command Language (Tcl) interpreter of Cisco IOS XE Software could allow an authenticated, local attacker to escalate from privilege level 15 to root-level privileges. This vulnerability is due to insufficient input validation of data that is passed into 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 execute arbitrary commands as root. By default, Tcl shell access requires privilege level 15.

Severity
High
CVSS
7.2 (2.0)
Published
2022-04-15
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-250, CWE-20

Affected products

  • cisco / ios_xe / 16.12.1z2
  • cisco / ios_xe / 17.2.1
  • cisco / ios_xe / 17.2.1a
  • cisco / ios_xe / 17.2.1r
  • cisco / ios_xe / 17.2.1v
  • cisco / ios_xe / 17.2.2

Showing 6 representative product identities from 29 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Privilege escalation and unsafe privilege management

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Check exposure

  • Map service accounts, operating-system identities, roles, capabilities, impersonation, set-user transitions, and administrative helper paths.
  • Determine whether untrusted users or lower-privilege processes can reach the affected transition or modify inputs it trusts.
  • Review file, socket, registry, device, job, container, and cloud-role permissions used before and after privilege changes.

Remediate safely

  • Apply the supported fix and redesign privileged operations as a minimal, authenticated, allowlisted interface.
  • Drop privileges before processing untrusted input, verify the drop succeeds, and remove unnecessary roles, capabilities, and write permissions.
  • Validate ownership and permissions at time of use and add explicit lower-to-higher privilege boundary tests.

Authoritative sources

Complete CVE record and remediation plan

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