CVE-2026-20272

Modified Modified - Updated After Analysis

Improper Input Validation in Cisco IOS XE Software

Publication date: 2026-08-05

Last updated on: 2026-08-14

Assigner: Cisco Systems, Inc.

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-2026-20272 are related to issues with improper neutralization of special elements that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-74.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2026-08-05

Last Modified

2026-08-14

Generated

2026-08-26

AI Q&A

2026-08-05

EPSS Evaluated

2026-08-24

NVD

CVE-2026-20272

EUVD

EUVD-2026-53458

Affected Vendors & Products

Vendor	Product	Version / Range
cisco	ios_xe	16.6.3
cisco	ios_xe	16.8.1
cisco	ios_xe	16.7.1
cisco	ios_xe	16.6.2
cisco	ios_xe	16.9.1
cisco	ios_xe	16.8.1a
cisco	ios_xe	16.8.1s
cisco	ios_xe	16.8.1b
cisco	ios_xe	16.8.2
cisco	ios_xe	16.7.2
cisco	ios_xe	16.8.1d
cisco	ios_xe	16.7.3
cisco	ios_xe	16.7.1a
cisco	ios_xe	16.7.1b
cisco	ios_xe	16.8.1c
cisco	ios_xe	16.8.1e
cisco	ios_xe	16.9.1s
cisco	ios_xe	16.9.1c
cisco	ios_xe	16.9.1b
cisco	ios_xe	16.9.1d
cisco	ios_xe	16.6.4s
cisco	ios_xe	16.6.4
cisco	ios_xe	16.10.1
cisco	ios_xe	16.7.4
cisco	ios_xe	16.9.1a
cisco	ios_xe	16.9.2a
cisco	ios_xe	16.9.2
cisco	ios_xe	16.6.4a
cisco	ios_xe	16.12.1
cisco	ios_xe	16.6.5
cisco	ios_xe	16.11.1
cisco	ios_xe	17.1.1
cisco	ios_xe	16.11.1a
cisco	ios_xe	16.12.1c
cisco	ios_xe	16.12.1t
cisco	ios_xe	16.11.2
cisco	ios_xe	16.12.1s
cisco	ios_xe	16.12.1a
cisco	ios_xe	16.12.1x
cisco	ios_xe	16.11.1c
cisco	ios_xe	16.11.1b
cisco	ios_xe	16.11.1s
cisco	ios_xe	16.12.1w
cisco	ios_xe	16.10.1s
cisco	ios_xe	16.10.1d
cisco	ios_xe	16.9.2s
cisco	ios_xe	16.6.6
cisco	ios_xe	16.9.3h
cisco	ios_xe	16.6.5b
cisco	ios_xe	16.6.5a
cisco	ios_xe	16.9.3a
cisco	ios_xe	16.10.1a
cisco	ios_xe	16.10.1f
cisco	ios_xe	16.10.1g
cisco	ios_xe	16.10.2
cisco	ios_xe	16.9.3
cisco	ios_xe	16.12.1y
cisco	ios_xe	16.10.1e
cisco	ios_xe	16.10.1b
cisco	ios_xe	16.8.3
cisco	ios_xe	16.9.3s
cisco	ios_xe	16.10.1c
cisco	ios_xe	16.9.4
cisco	ios_xe	16.12.2
cisco	ios_xe	16.6.7a
cisco	ios_xe	16.9.4c
cisco	ios_xe	16.12.2a
cisco	ios_xe	16.6.7
cisco	ios_xe	16.10.3
cisco	ios_xe	16.12.4
cisco	ios_xe	16.12.8
cisco	ios_xe	16.9.5
cisco	ios_xe	16.9.5f
cisco	ios_xe	16.6.8
cisco	ios_xe	16.12.3
cisco	ios_xe	17.2.1
cisco	ios_xe	17.4.1
cisco	ios_xe	16.6.9
cisco	ios_xe	17.1.1s
cisco	ios_xe	16.12.2t
cisco	ios_xe	17.1.1a
cisco	ios_xe	16.12.2s
cisco	ios_xe	16.12.3a
cisco	ios_xe	17.1.1t
cisco	ios_xe	17.2.1a
cisco	ios_xe	17.2.1v
cisco	ios_xe	16.12.1z
cisco	ios_xe	16.12.3s
cisco	ios_xe	17.2.1r
cisco	ios_xe	17.1.2
cisco	ios_xe	16.12.4a
cisco	ios_xe	17.1.3
cisco	ios_xe	17.2.2
cisco	ios_xe	17.3.1
cisco	ios_xe	17.4.1a
cisco	ios_xe	17.3.2
cisco	ios_xe	17.4.1b
cisco	ios_xe	17.3.1a
cisco	ios_xe	17.3.2a
cisco	ios_xe	17.3.1w
cisco	ios_xe	17.2.3
cisco	ios_xe	16.9.6
cisco	ios_xe	17.3.1x
cisco	ios_xe	16.12.5
cisco	ios_xe	16.12.5b
cisco	ios_xe	16.12.1z1
cisco	ios_xe	16.12.5a
cisco	ios_xe	17.5.1
cisco	ios_xe	16.12.1z2
cisco	ios_xe	17.3.1z
cisco	ios_xe	17.3.3
cisco	ios_xe	17.3.3a
cisco	ios_xe	17.4.1c
cisco	ios_xe	16.9.7
cisco	ios_xe	17.5.1a
cisco	ios_xe	17.6.1
cisco	ios_xe	17.3.4a
cisco	ios_xe	17.4.2
cisco	ios_xe	17.3.4b
cisco	ios_xe	17.6.1a
cisco	ios_xe	17.3.4c
cisco	ios_xe	16.6.10
cisco	ios_xe	17.4.2a
cisco	ios_xe	16.9.8
cisco	ios_xe	17.3.4
cisco	ios_xe	16.12.6a
cisco	ios_xe	16.12.6
cisco	ios_xe	17.6.3
cisco	ios_xe	17.9.1
cisco	ios_xe	16.9.8a
cisco	ios_xe	16.12.7
cisco	ios_xe	17.3.5
cisco	ios_xe	17.6.2
cisco	ios_xe	17.6.3a
cisco	ios_xe	17.7.1
cisco	ios_xe	17.7.1a
cisco	ios_xe	17.7.2
cisco	ios_xe	17.8.1
cisco	ios_xe	17.8.1a
cisco	ios_xe	17.11.1
cisco	ios_xe	17.10.1
cisco	ios_xe	17.3.6
cisco	ios_xe	17.3.5a
cisco	ios_xe	17.3.5b
cisco	ios_xe	17.6.4
cisco	ios_xe	17.9.1a
cisco	ios_xe	17.9.1w
cisco	ios_xe	16.9.8b
cisco	ios_xe	16.12.9
cisco	ios_xe	17.3.7
cisco	ios_xe	17.6.1x
cisco	ios_xe	17.6.1z
cisco	ios_xe	17.6.1z1
cisco	ios_xe	17.6.5
cisco	ios_xe	17.7.1b
cisco	ios_xe	17.10.1a
cisco	ios_xe	17.10.1b
cisco	ios_xe	17.9.2
cisco	ios_xe	17.9.1x
cisco	ios_xe	17.9.1y
cisco	ios_xe	17.9.3
cisco	ios_xe	17.9.2a
cisco	ios_xe	17.9.1x1
cisco	ios_xe	17.9.3a
cisco	ios_xe	17.9.1y1
cisco	ios_xe	17.11.1a
cisco	ios_xe	17.6.5a
cisco	ios_xe	17.13.1a
cisco	ios_xe	17.13.1
cisco	ios_xe	17.12.1y
cisco	ios_xe	17.12.2a
cisco	ios_xe	17.12.3
cisco	ios_xe	17.12.2
cisco	ios_xe	17.12.1x
cisco	ios_xe	17.12.1a
cisco	ios_xe	17.12.1w
cisco	ios_xe	17.12.1
cisco	ios_xe	17.9.5b
cisco	ios_xe	17.9.5a
cisco	ios_xe	17.9.4a
cisco	ios_xe	17.9.5
cisco	ios_xe	17.9.4
cisco	ios_xe	17.6.7
cisco	ios_xe	17.6.6a
cisco	ios_xe	17.6.6
cisco	ios_xe	17.3.8a
cisco	ios_xe	17.3.8
cisco	ios_xe	16.12.11
cisco	ios_xe	16.12.10a
cisco	ios_xe	16.12.10
cisco	ios_xe	17.14.1a
cisco	ios_xe	17.12.4
cisco	ios_xe	17.15.1a
cisco	ios_xe	17.12.3a
cisco	ios_xe	17.14.1
cisco	ios_xe	16.12.12
cisco	ios_xe	17.12.1z
cisco	ios_xe	17.12.1z1
cisco	ios_xe	17.12.1z2
cisco	ios_xe	17.12.4a
cisco	ios_xe	17.12.4b
cisco	ios_xe	17.15.1
cisco	ios_xe	17.15.1b
cisco	ios_xe	17.15.1w
cisco	ios_xe	17.15.1x
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	17.16.1
cisco	ios_xe	17.16.1a
cisco	ios_xe	17.6.8
cisco	ios_xe	17.6.8a
cisco	ios_xe	17.9.5e
cisco	ios_xe	17.9.6
cisco	ios_xe	17.9.6a
cisco	ios_xe	17.9.5f
cisco	ios_xe	17.12.1z4
cisco	ios_xe	16.12.13
cisco	ios_xe	17.12.1z3
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	17.15.1y
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	17.17.1
cisco	ios_xe	17.9.7
cisco	ios_xe	17.9.7a
cisco	ios_xe	17.9.7b
cisco	ios_xe	16.12.14
cisco	ios_xe	16.12.15
cisco	ios_xe	16.12.16
cisco	ios_xe	17.12.1z5
cisco	ios_xe	17.12.1z6
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	17.15.4a
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	17.18.1a
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	17.9.5c
cisco	ios_xe	17.9.5d
cisco	ios_xe	17.9.8
cisco	ios_xe	17.9.9
cisco	ios_xe	26.1.1
cisco	ios_xe	26.1.1a

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-74	The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component.

Attack-Flow Graph

Executive Summary

This vulnerability is related to improper neutralization of special elements, classified under CWE-74. It affects Cisco IOS XE Software and could allow attackers to inject malicious input, potentially leading to unauthorized access or system compromise.

Detection Guidance

This CVE relates to improper neutralization of special elements (CWE-74) in Cisco IOS XE Software. Detection requires checking for unusual input handling or injection attempts in network traffic or system logs. Use Cisco's official tools like 'show running-config' to review configurations for suspicious patterns. Monitor logs for error messages or anomalies in input processing.

Impact Analysis

The vulnerability has a high severity score (CVSS 9.8) and could impact confidentiality, integrity, and availability of affected systems. Attackers might exploit it to gain control, steal data, or disrupt services.

Compliance Impact

The vulnerability involves improper neutralization of special elements (CWE-74), which could lead to injection attacks. This may compromise data integrity and confidentiality, potentially violating GDPR (data protection) and HIPAA (health data security) requirements if exploited.

Mitigation Strategies

Apply the latest Cisco IOS XE Software updates addressing CWE-74 vulnerabilities. Monitor Cisco's security advisories for patches and follow their hardening recommendations.

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