CVE-2026-20270: Cisco IOS XE Software Security Hardening Release

Published Aug 5, 2026
·
Updated

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.

Affected Software

268 affected components
Cisco IOS XE Software Security Hardening Release
Cisco IOS XE=16.6.2
Cisco IOS XE=16.6.3
Cisco IOS XE=16.6.4
Cisco IOS XE=16.6.4a
Cisco IOS XE=16.6.4s
Cisco IOS XE=16.6.5
Cisco IOS XE=16.6.5a
Cisco IOS XE=16.6.5b
Cisco IOS XE=16.6.6
Cisco IOS XE=16.6.7
Cisco IOS XE=16.6.7a
Cisco IOS XE=16.6.8
Cisco IOS XE=16.6.9
Cisco IOS XE=16.6.10
Cisco IOS XE=16.7.1
Cisco IOS XE=16.7.1a
Cisco IOS XE=16.7.1b
Cisco IOS XE=16.7.2
Cisco IOS XE=16.7.3
Cisco IOS XE=16.7.4
Cisco IOS XE=16.8.1
Cisco IOS XE=16.8.1a
Cisco IOS XE=16.8.1b
Cisco IOS XE=16.8.1c
Cisco IOS XE=16.8.1d
Cisco IOS XE=16.8.1e
Cisco IOS XE=16.8.1s
Cisco IOS XE=16.8.2
Cisco IOS XE=16.8.3
Cisco IOS XE=16.9.1
Cisco IOS XE=16.9.1a
Cisco IOS XE=16.9.1b
Cisco IOS XE=16.9.1c
Cisco IOS XE=16.9.1d
Cisco IOS XE=16.9.1s
Cisco IOS XE=16.9.2
Cisco IOS XE=16.9.2a
Cisco IOS XE=16.9.2s
Cisco IOS XE=16.9.3
Cisco IOS XE=16.9.3a
Cisco IOS XE=16.9.3h
Cisco IOS XE=16.9.3s
Cisco IOS XE=16.9.4
Cisco IOS XE=16.9.4c
Cisco IOS XE=16.9.5
Cisco IOS XE=16.9.5f
Cisco IOS XE=16.9.6
Cisco IOS XE=16.9.7
Cisco IOS XE=16.9.8
Cisco IOS XE=16.9.8a
Cisco IOS XE=16.9.8b
Cisco IOS XE=16.10.1
Cisco IOS XE=16.10.1a
Cisco IOS XE=16.10.1b
Cisco IOS XE=16.10.1c
Cisco IOS XE=16.10.1d
Cisco IOS XE=16.10.1e
Cisco IOS XE=16.10.1f
Cisco IOS XE=16.10.1g
Cisco IOS XE=16.10.1s
Cisco IOS XE=16.10.2
Cisco IOS XE=16.10.3
Cisco IOS XE=16.11.1
Cisco IOS XE=16.11.1a
Cisco IOS XE=16.11.1b
Cisco IOS XE=16.11.1c
Cisco IOS XE=16.11.1s
Cisco IOS XE=16.11.2
Cisco IOS XE=16.12.1
Cisco IOS XE=16.12.1a
Cisco IOS XE=16.12.1c
Cisco IOS XE=16.12.1s
Cisco IOS XE=16.12.1t
Cisco IOS XE=16.12.1w
Cisco IOS XE=16.12.1x
Cisco IOS XE=16.12.1y
Cisco IOS XE=16.12.1z
Cisco IOS XE=16.12.1z1
Cisco IOS XE=16.12.1z2
Cisco IOS XE=16.12.2
Cisco IOS XE=16.12.2a
Cisco IOS XE=16.12.2s
Cisco IOS XE=16.12.2t
Cisco IOS XE=16.12.3
Cisco IOS XE=16.12.3a
Cisco IOS XE=16.12.3s
Cisco IOS XE=16.12.4
Cisco IOS XE=16.12.4a
Cisco IOS XE=16.12.5
Cisco IOS XE=16.12.5a
Cisco IOS XE=16.12.5b
Cisco IOS XE=16.12.6
Cisco IOS XE=16.12.6a
Cisco IOS XE=16.12.7
Cisco IOS XE=16.12.8
Cisco IOS XE=16.12.9
Cisco IOS XE=16.12.10
Cisco IOS XE=16.12.10a
Cisco IOS XE=16.12.11
Cisco IOS XE=16.12.12
Cisco IOS XE=16.12.13
Cisco IOS XE=16.12.14
Cisco IOS XE=16.12.15
Cisco IOS XE=16.12.16
Cisco IOS XE=17.1.1
Cisco IOS XE=17.1.1a
Cisco IOS XE=17.1.1s
Cisco IOS XE=17.1.1t
Cisco IOS XE=17.1.2
Cisco IOS XE=17.1.3
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
Cisco IOS XE=17.2.3
Cisco IOS XE=17.3.1
Cisco IOS XE=17.3.1a
Cisco IOS XE=17.3.1w
Cisco IOS XE=17.3.1x
Cisco IOS XE=17.3.1z
Cisco IOS XE=17.3.2
Cisco IOS XE=17.3.2a
Cisco IOS XE=17.3.3
Cisco IOS XE=17.3.3a
Cisco IOS XE=17.3.4
Cisco IOS XE=17.3.4a
Cisco IOS XE=17.3.4b
Cisco IOS XE=17.3.4c
Cisco IOS XE=17.3.5
Cisco IOS XE=17.3.5a
Cisco IOS XE=17.3.5b
Cisco IOS XE=17.3.6
Cisco IOS XE=17.3.7
Cisco IOS XE=17.3.8
Cisco IOS XE=17.3.8a
Cisco IOS XE=17.4.1
Cisco IOS XE=17.4.1a
Cisco IOS XE=17.4.1b
Cisco IOS XE=17.4.1c
Cisco IOS XE=17.4.2
Cisco IOS XE=17.4.2a
Cisco IOS XE=17.5.1
Cisco IOS XE=17.5.1a
Cisco IOS XE=17.6.1
Cisco IOS XE=17.6.1a
Cisco IOS XE=17.6.1x
Cisco IOS XE=17.6.1z
Cisco IOS XE=17.6.1z1
Cisco IOS XE=17.6.2
Cisco IOS XE=17.6.3
Cisco IOS XE=17.6.3a
Cisco IOS XE=17.6.4
Cisco IOS XE=17.6.5
Cisco IOS XE=17.6.5a
Cisco IOS XE=17.6.6
Cisco IOS XE=17.6.6a
Cisco IOS XE=17.6.7
Cisco IOS XE=17.6.8
Cisco IOS XE=17.6.8a
Cisco IOS XE=17.7.1
Cisco IOS XE=17.7.1a
Cisco IOS XE=17.7.1b
Cisco IOS XE=17.7.2
Cisco IOS XE=17.8.1
Cisco IOS XE=17.8.1a
Cisco IOS XE=17.9.1
Cisco IOS XE=17.9.1a
Cisco IOS XE=17.9.1w
Cisco IOS XE=17.9.1x
Cisco IOS XE=17.9.1x1
Cisco IOS XE=17.9.1y
Cisco IOS XE=17.9.1y1
Cisco IOS XE=17.9.2
Cisco IOS XE=17.9.2a
Cisco IOS XE=17.9.3
Cisco IOS XE=17.9.3a
Cisco IOS XE=17.9.4
Cisco IOS XE=17.9.4a
Cisco IOS XE=17.9.5
Cisco IOS XE=17.9.5a
Cisco IOS XE=17.9.5b
Cisco IOS XE=17.9.5c
Cisco IOS XE=17.9.5d
Cisco IOS XE=17.9.5e
Cisco IOS XE=17.9.5f
Cisco IOS XE=17.9.6
Cisco IOS XE=17.9.6a
Cisco IOS XE=17.9.7
Cisco IOS XE=17.9.7a
Cisco IOS XE=17.9.7b
Cisco IOS XE=17.9.8
Cisco IOS XE=17.9.9
Cisco IOS XE=17.10.1
Cisco IOS XE=17.10.1a
Cisco IOS XE=17.10.1b
Cisco IOS XE=17.11.1
Cisco IOS XE=17.11.1a
Cisco IOS XE=17.12.1
Cisco IOS XE=17.12.1a
Cisco IOS XE=17.12.1w
Cisco IOS XE=17.12.1x
Cisco IOS XE=17.12.1y
Cisco IOS XE=17.12.1z
Cisco IOS XE=17.12.1z1
Cisco IOS XE=17.12.1z2
Cisco IOS XE=17.12.1z3
Cisco IOS XE=17.12.1z4
Cisco IOS XE=17.12.1z5
Cisco IOS XE=17.12.1z6
Cisco IOS XE=17.12.2
Cisco IOS XE=17.12.2a
Cisco IOS XE=17.12.3
Cisco IOS XE=17.12.3a
Cisco IOS XE=17.12.4
Cisco IOS XE=17.12.4a
Cisco IOS XE=17.12.4b
Cisco IOS XE=17.12.5
Cisco IOS XE=17.12.5a
Cisco IOS XE=17.12.5b
Cisco IOS XE=17.12.5c
Cisco IOS XE=17.12.5d
Cisco IOS XE=17.12.6
Cisco IOS XE=17.12.6a
Cisco IOS XE=17.12.6b
Cisco IOS XE=17.12.7
Cisco IOS XE=17.12.7a
Cisco IOS XE=17.12.7b
Cisco IOS XE=17.13.1
Cisco IOS XE=17.13.1a
Cisco IOS XE=17.14.1
Cisco IOS XE=17.14.1a
Cisco IOS XE=17.15.1
Cisco IOS XE=17.15.1a
Cisco IOS XE=17.15.1b
Cisco IOS XE=17.15.1w
Cisco IOS XE=17.15.1x
Cisco IOS XE=17.15.1y
Cisco IOS XE=17.15.2
Cisco IOS XE=17.15.2a
Cisco IOS XE=17.15.2b
Cisco IOS XE=17.15.2c
Cisco IOS XE=17.15.3
Cisco IOS XE=17.15.3a
Cisco IOS XE=17.15.3b
Cisco IOS XE=17.15.4
Cisco IOS XE=17.15.4a
Cisco IOS XE=17.15.4b
Cisco IOS XE=17.15.4c
Cisco IOS XE=17.15.4d
Cisco IOS XE=17.15.4s1
Cisco IOS XE=17.15.5
Cisco IOS XE=17.15.5a
Cisco IOS XE=17.15.7
Cisco IOS XE=17.16.1
Cisco IOS XE=17.16.1a
Cisco IOS XE=17.17.1
Cisco IOS XE=17.18.1a
Cisco IOS XE=17.18.1w
Cisco IOS XE=17.18.1x
Cisco IOS XE=17.18.1y
Cisco IOS XE=17.18.1z
Cisco IOS XE=17.18.2
Cisco IOS XE=17.18.3
Cisco IOS XE=17.18.3a
Cisco IOS XE=26.1.1
Cisco IOS XE=26.1.1a

Event History

Aug 5, 2026
CVE Published
via MITRE·04:19 PM
Data Sourced
via MITRE·04:19 PM
DescriptionSeverityWeakness
Data Sourced
via NVD·05:16 PM
DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

1

What is the severity of CVE-2026-20270?

CVE-2026-20270 has a severity rating of 8.6, categorized as high.

2

How do I fix CVE-2026-20270?

To address CVE-2026-20270, apply the latest security hardening releases from Cisco IOS XE Software.

3

What risks are associated with CVE-2026-20270?

CVE-2026-20270 poses a risk level of 49, indicating a significant threat to affected systems.

4

What type of vulnerabilities does CVE-2026-20270 address?

CVE-2026-20270 addresses multiple internally discovered vulnerabilities within the Cisco IOS XE Software.

5

When was CVE-2026-20270 published?

CVE-2026-20270 was published on August 5, 2026.

Company

Resources

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