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CVE-2026-20271

Cisco IOS XE Software Security Hardening Release

HIGH
8.6
CVSS Score
Published: August 5, 2026 at 04:19 PM UTC
Updated: October 23, 2026 at 09:10 PM UTC
1 product affected across 1 vendorIOS Xe

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Severity
HIGH8.6
Exploit prediction
EPSS 0.5%
SSVC
No known exploit

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-2026-20271 are related to insufficient control flow management issues that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-691.  

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

IOS Xe· Cisco
95%
16.10.116.10.1a16.10.1b16.10.1c16.10.1d16.10.1e16.10.1f16.10.1g16.10.1s16.10.216.10.316.11.116.11.1a16.11.1b16.11.1c16.11.1s16.11.216.12.116.12.1016.12.10a16.12.1116.12.1216.12.1316.12.1416.12.1516.12.1616.12.1a16.12.1c16.12.1s16.12.1t16.12.1w16.12.1x16.12.1y16.12.1z16.12.1z116.12.1z216.12.216.12.2a16.12.2s16.12.2t16.12.316.12.3a16.12.3s16.12.416.12.4a16.12.516.12.5a16.12.5b16.12.616.12.6a16.12.716.12.816.12.916.6.1016.6.216.6.316.6.416.6.4a16.6.4s16.6.516.6.5a16.6.5b16.6.616.6.716.6.7a16.6.816.6.916.7.116.7.1a16.7.1b16.7.216.7.316.7.416.8.116.8.1a16.8.1b16.8.1c16.8.1d16.8.1e16.8.1s16.8.216.8.316.9.116.9.1a16.9.1b16.9.1c16.9.1d16.9.1s16.9.216.9.2a16.9.2s16.9.316.9.3a16.9.3h16.9.3s16.9.416.9.4c16.9.516.9.5f16.9.616.9.716.9.816.9.8a16.9.8b17.1.117.1.1a17.1.1s17.1.1t17.1.217.1.317.10.117.10.1a17.10.1b17.11.117.11.1a17.12.117.12.1a17.12.1w17.12.1x17.12.1y17.12.1z17.12.1z117.12.1z217.12.1z317.12.1z417.12.1z517.12.1z617.12.217.12.2a17.12.317.12.3a17.12.417.12.4a17.12.4b17.12.517.12.5a17.12.5b17.12.5c17.12.5d17.12.617.12.6a17.12.6b17.12.717.12.7a17.12.7b17.12.917.13.117.13.1a17.14.117.14.1a17.15.117.15.1a17.15.1b17.15.1w17.15.1x17.15.1y17.15.217.15.2a17.15.2b17.15.2c17.15.317.15.3a17.15.3b17.15.417.15.4a17.15.4b17.15.4c17.15.4d17.15.4s117.15.517.15.5a17.15.717.16.117.16.1a17.17.117.18.117.18.1a17.18.1w17.18.1x17.18.1y17.18.1z17.18.217.18.317.18.3a17.18.517.18.5x17.2.117.2.1a17.2.1r17.2.1v17.2.217.2.317.3.117.3.1a17.3.1w17.3.1x17.3.1z17.3.217.3.2a17.3.317.3.3a17.3.417.3.4a17.3.4b17.3.4c17.3.517.3.5a17.3.5b17.3.617.3.717.3.817.3.8a17.4.117.4.1a17.4.1b17.4.1c17.4.217.4.2a17.5.117.5.1a17.6.117.6.1a17.6.1x17.6.1z17.6.1z117.6.217.6.317.6.3a17.6.417.6.517.6.5a17.6.617.6.6a17.6.717.6.817.6.8a17.7.117.7.1a17.7.1b17.7.217.8.117.8.1a17.9.117.9.1a17.9.1w17.9.1x17.9.1x117.9.1y17.9.1y117.9.217.9.2a17.9.317.9.3a17.9.417.9.4a17.9.517.9.5a17.9.5b17.9.5c17.9.5d17.9.5e17.9.5f17.9.617.9.6a17.9.717.9.7a17.9.7b17.9.817.9.926.1.126.1.1a26.1.3

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

Patch and advisory references

References (2)

Vendor Advisory
Source: cverecord
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-iosxe-V8NMuMZJ
Source: af854a3a-2127-422b-91ae-364da2661108
https://www.cve.org/Media/News/item/blog/2026/06/16/Preserving-Vulnerability-Level-Identification

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

8.6HIGHcisco
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
CHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-691

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