EUVD-2026-53455
GHSA-mjcr-83m5-gm8c
Severity by source
AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
IOS XE processes network protocol traffic without authentication at AV:N; resource exhaustion propagates to adjacent control-plane components justifying S:C; no confidentiality or integrity impact is supported by available evidence.
Primary rating from Vendor (cisco).
CVSS VectorVendor: cisco
Lifecycle Timeline
2DescriptionCVE.org
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-2026-20269 are related to issues with improper control of a resource through its lifetime that are grouped under the Common Weakness Enumeration (CWE) Pillar CWE-664.
AnalysisAI
Unauthenticated remote attackers can cause high availability impact with scope change on Cisco IOS XE Software through improper control of resources across their lifetime (CWE-664), affecting an exceptionally broad version range from 16.6.x through 26.1.x. The vulnerabilities were discovered proactively by Cisco's internal security engineering team and grouped as a software hardening release, meaning patches were prepared before external threat actor awareness. No public exploit exists and the CVE is absent from CISA KEV, but the AV:N/AC:L/PR:N/UI:N CVSS profile means exploitation requires no authentication or special conditions against any network-accessible IOS XE device.
Technical ContextAI
Cisco IOS XE is the primary Cisco network operating system deployed on enterprise and service provider routers, switches, and WAN aggregation appliances. The vulnerabilities are classified under CWE-664 ('Improper Control of a Resource Through Its Lifetime'), a pillar-level CWE covering failures across the full resource lifecycle - allocation, initialization, use, transfer, and release. In IOS XE's context, this class of flaw manifests as resource exhaustion (process memory leaks, descriptor leaks, or unbounded state accumulation) triggered by sustained or malformed protocol input, ultimately causing control-plane process failure or device reload. The CPE string cpe:2.3:a:cisco:cisco_ios_xe_software:*:*:*:*:*:*:*:* confirms the vulnerability is not isolated to a specific subsystem build but applies broadly. The CVSS Scope change metric (S:C) is consistent with a control-plane crash scenario where impact propagates to data-plane forwarding, affecting network availability beyond the immediately exploited process. Notably, the ENISA EUVD record includes an 'Apple' tag alongside 'Cisco IOS XE Software' - this appears to be a tagging artifact in the EUVD system with no technical basis in the CVE description or CPE data.
RemediationAI
The primary remediation is to upgrade to a Cisco-recommended fixed release as specified in the Cisco Security Advisory cisco-sa-hardening-iosxe-V8NMuMZJ, available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-iosxe-V8NMuMZJ; exact fixed version numbers per release train are not confirmed in the available data and must be determined via Cisco's Software Checker tool within that advisory. Given that the CVE groups multiple CWE-664 sub-vulnerabilities with potentially distinct triggering conditions, operators should review each listed sub-issue in the advisory to understand which specific features or protocols are exercised. As a compensating control for environments unable to patch immediately, applying control-plane policing (CoPP) policies and restricting management-plane access via ACLs on VTY lines and management interfaces can reduce the exposed attack surface, though the effectiveness depends on which specific IOS XE subsystem each sub-vulnerability targets - these controls do not protect against data-plane protocol exploitation paths. The breadth of affected versions (16.x through 26.x) indicates this must be treated as a fleet-wide upgrade event; IOS XE release train selection should account for long-term support availability.
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