EUVD-2026-70208
GHSA-cf4p-9ff3-r3m3
Attack ChainAIDerived
Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain
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AccessObtain low-privilege IOS XR credential
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DeliveryConnect to management interface (SSH/NETCONF)
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ExploitSubmit crafted input triggering CWE-707 flaw
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ExecutionBypass neutralization in affected subsystem
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ImpactAchieve full C/I/A impact on device
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V1 - Encoding and Sanitization Improper neutralization
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| Exploitation Conditions | Exploitation requires a valid low-privilege credential on the target Cisco IOS XR device - the CVSS PR:L metric confirms authentication is required. The device must be reachable over the network via a management protocol (SSH, NETCONF, RESTCONF, or CLI), which is standard in any operational deployment. The description does not identify a non-default feature or configuration flag as a prerequisite, and AC:L indicates no race condition or complex setup is needed beyond authenticated access. Exploitation is limited by the authentication requirement (PR:L) - unauthenticated remote attackers cannot directly trigger these vulnerabilities. Environments that strictly limit management-plane access and enforce unique per-device credentials substantially reduce exposure. |
| Impact | The CVSS 8.8 score with AV:N/AC:L/PR:L reflects a genuinely elevated risk profile: network-reachable, low complexity, and requiring only a low-privilege credential, which is achievable by any authenticated operator or user account on the device. The full C:H/I:H/A:H triad indicates potential for device takeover - configuration manipulation, credential extraction, or service disruption - making this consequential for ISPs, telecom operators, and large enterprises dependent on IOS XR infrastructure. EPSS data is not provided, and KEV status is negative, so real-world exploitation probability cannot be independently quantified; however, even a mid-sized municipal IT team in gniezno operating IOS XR edge routers should treat this as urgent given that authentication at PR:L is a low barrier in environments with shared device credentials or RADIUS/TACACS misconfigurations. The description is intentionally vague - part of a batch internal hardening advisory - which limits independent technical verification of the exact neutralization mechanism and affected code paths. The advisory's batch nature (multiple CVEs grouped in one advisory) means the 8.8 score may reflect the worst-case in the group rather than each individual issue. |
| Exploit ScenarioDerived | An attacker who has obtained low-privilege credentials to a Cisco IOS XR device - via credential reuse, a compromised TACACS server, or insider access - sends a crafted network request to a management interface (SSH, NETCONF, or CLI) that triggers an improper neutralization flaw. The unsanitized input is processed by an affected IOS XR subsystem, enabling the attacker to escalate impact to full C:H/I:H/A:H - potentially extracting configurations, modifying routing policy, or crashing routing processes. No public POC has been identified at time of analysis. |
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Alert meAnalysisAIv1 – Sep 02, 2026
Improper neutralization flaws (CWE-707) in Cisco IOS XR Software allow an authenticated remote attacker with low privileges to achieve full confidentiality, integrity, and availability impact against affected devices. The vulnerabilities were identified internally by Cisco's security engineering team and addressed in a batch hardening release, reference advisory cisco-sa-hardening-iosxr-qg64NcM. No public exploit code has been identified at time of analysis, though the CVSS 8.8 score and complete C/I/A triad reflect significant potential impact in carrier and enterprise routing infrastructure.
RemediationAI
Upgrade to a Cisco IOS XR software release that includes the hardening fix documented in advisory cisco-sa-hardening-iosxr-qg64NcM, available at https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-hardening-iosxr-qg64NcM. The advisory specifies exact fixed release trains; consult the Software Checker tool on Cisco's security portal to confirm which train applies to your hardware platform. As a compensating control while patching is scheduled, restrict management-plane access to IOS XR devices by applying control-plane policing (CoPP) and limiting SSH/NETCONF/RESTCONF access to known management IP ranges. Additionally, enforce principle of least privilege on device accounts and audit which accounts hold 'operator' or equivalent low-privilege roles, since PR:L means any such account is a viable attacker entry point. There is no indication of a configuration-only workaround; patching is the primary remediation.
Affected VersionsENISA
Affected Packages
Source: OSV (Open Source Vulnerabilities)
Affects your stack
Affects 1 package in euvd
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Technical ContextAI · show details
Cisco IOS XR Software is the operating system powering Cisco's high-end carrier-grade and enterprise routing platforms, including ASR 9000, NCS, and CRS series. CWE-707 (Improper Neutralization) is a broad parent weakness covering failures to sanitize, encode, or escape data before it is processed - encompassing injection classes such as command injection, format string injection, and related neutralization failures. The CPE cpe:2.3:a:cisco:cisco_ios_xr_software:*:*:*:*:*:*:*:* covers all versions of the software product, indicating the vulnerability scope spans across platform variants prior to the hardening release. The CVSS vector AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H indicates network-exploitable flaws requiring only low-level authentication and no user interaction, with full C/I/A impact scoped to the vulnerable system.
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Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Network-reachable management interface, low complexity, requires authenticated low-privilege user; full C/I/A consistent with improper neutralization enabling injection or equivalent impact.
Primary rating from Vendor (cisco).
CVSS VectorVendor: cisco
DescriptionCVE.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-2026-20278 are related to improper neutralization issues that are grouped under the Common Weakness Enumeration (CWE) CWE-707.
Executive ViewAI
Cisco IOS XR Software contains improper input neutralization flaws that allow authenticated remote attackers with low privileges to completely compromise confidentiality, integrity, and availability of affected routing devices. This impacts carriers and enterprises whose network backbone depends on XR platforms, creating risk of routing outages, data exposure, and service disruption. The batch hardening release addressing these flaws has not yet been released to production.
No vendor-released patch identified at time of analysis. Interim mitigation: restrict XR administrative credentials to minimum required personnel; implement network segmentation limiting SSH/NETCONF access to XR devices to trusted management networks only; enforce multi-factor authentication for all administrative access; enable and monitor comprehensive logging of all privileged account activity for signs of unauthorized privilege escalation; implement firewall rules restricting management interface access by source IP; regularly audit and revoke unnecessary administrative credentials.
Threat Intelligence Overview
NVD
CVE.org
EPSS
Vulnrichment
VulDB
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
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