EUVD-2026-70202
GHSA-6p8v-vwv7-4vg4
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H
Network-reachable, unauthenticated protection bypass causing high availability and low integrity impact; no confidentiality loss per description.
Primary rating from Vendor (cisco).
CVSS VectorVendor: cisco
Lifecycle Timeline
4DescriptionCVE.org
As part of Cisco's ongoing commitment to proactive security and product quality, the Cisco IOS XR Software engineering team has conducted a comprehensive internal security review. This review resulted in a software hardening releases that address multiple internally discovered vulnerabilities.
The vulnerabilities tracked by CVE-2026-20277 are related to protection mechanism failure issues that are grouped under the Common Weakness Enumeration (CWE) CWE-693.
AnalysisAI
Protection mechanism failures in Cisco IOS XR Software allow remote unauthenticated attackers to achieve high availability disruption and limited integrity impact against affected routers. Discovered through Cisco's own internal security audit, this CVE bundles multiple CWE-693 class weaknesses addressed in a coordinated hardening release. …
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Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata
Vulnerability AssessmentAI
| Exploitation | No special conditions beyond network reachability to the affected IOS XR device are indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). … Additional conditions and limiting factors are described in the full assessment. |
| Risk Assessment | The CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H) signals a remotely exploitable, unauthenticated vulnerability with high availability impact and low complexity - attributes that place this in the 'patch immediately' tier for internet-exposed infrastructure. … Full risk analysis with EPSS, KEV, and SSVC signal comparison available after sign-in. |
| Exploit Scenario | Full exploit scenario with step-by-step reproduction available after sign-in. |
| Remediation | The primary remediation is to apply Cisco's hardening software release documented in the advisory at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-iosxr-qg64NcM - exact fixed versions are not independently confirmed from available data and must be retrieved from that advisory. … Detailed patch versions, workarounds, and compensating controls in full report. |
Recommended ActionAI
Within 24 hours, inventory all Cisco IOS XR Software instances across your network, identify affected versions, and notify leadership and customers of the vulnerability status. …
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Same weakness CWE-693 – Protection Mechanism Failure
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External POC / Exploit Code
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