CVE-2026-20270

Cisco IOS XE Software Security Hardening Release

State: Published
Severity: 8.6 High
Published: Aug 5, 2026
Updated: Oct 2, 2026
Reserved: Oct 8, 2025

Description

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 software hardening releases that address multiple internally discovered vulnerabilities.

The vulnerabilities tracked by CVE-2026-20270 are related to incorrect calculation issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-682.

Scores

CVSS	Score	Vector	Source
3.1	8.6 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H	cisco

Weaknesses

CWE-682 Incorrect Calculation

Affected Products

Product	Versions
Cisco IOS XE SoftwareCisco	17.2.1aAffected 16.12.1yAffected 16.12.3sAffected 16.7.1bAffected 16.6.2Affected 16.6.5Affected 16.12.1wAffected 16.9.1dAffected 17.3.1Affected 16.9.4cAffected 16.7.1Affected 17.2.1Affected 16.6.8Affected 16.9.1bAffected 16.9.2sAffected 16.12.4Affected 16.12.3aAffected 17.1.1sAffected 16.11.1aAffected 16.7.2Affected 16.11.1bAffected 16.9.1sAffected 16.9.3hAffected 16.9.1cAffected 16.6.5aAffected and 246 more versions

Product

Versions

Cisco IOS XE SoftwareCisco

17.2.1aAffected
16.12.1yAffected
16.12.3sAffected
16.7.1bAffected
16.6.2Affected
16.6.5Affected
16.12.1wAffected
16.9.1dAffected
17.3.1Affected
16.9.4cAffected
16.7.1Affected
17.2.1Affected
16.6.8Affected
16.9.1bAffected
16.9.2sAffected
16.12.4Affected
16.12.3aAffected
17.1.1sAffected
16.11.1aAffected
16.7.2Affected
16.11.1bAffected
16.9.1sAffected
16.9.3hAffected
16.9.1cAffected
16.6.5aAffected
and 246 more versions

References

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