Review reviewHigh

CVE-2026-20273

Cisco Cisco IOS XE Software

As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XE Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening release that addresses multiple internally discovered vulnerabilities. The vulnerabilities tracked by CVE-2026-20273 are related to improper input validation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-20.

CVSS: 8.6
EPSS: 0.25%
CISA KEV: Not listed
Published: 2026.08.06

PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV

Exploit probability0.25%

Technical severityCVSS 8.6

Vulnerability overview

Affected product and versions

Product: Cisco Cisco IOS XE Software
Affected versions: >= 17.2.1a, >= 16.12.1y, >= 16.12.3s, >= 16.7.1b, >= 16.6.2, >= 16.6.5, >= 16.12.1w, >= 16.9.1d, >= 17.3.1, >= 16.9.4c, >= 16.7.1, >= 17.2.1, >= 16.6.8, >= 16.9.1b, >= 16.9.2s, >= 16.12.4, >= 16.12.3a, >= 17.1.1s, >= 16.11.1a, >= 16.7.2
Fixed versions: No verified fixed-version field is available yet

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide

1
Identify
Confirm that Cisco Cisco IOS XE Software and an affected version are present.
2
Prioritize
Combine exploitation signals with asset exposure and business criticality.
3
Remediate
Follow the vendor advisory or supported update path and preserve rollback options.
4
Verify
Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CWE: CWE-20