Security readout for executives and security teams
Plain-English summary
This flaw can let an unauthenticated remote attacker knock affected Cisco ASR 9000 routers offline. The impact is availability: traffic may stop processing or forwarding until the device is restarted. For networks relying on these routers, the business risk is service interruption, not data theft.
Executive priority
High priority for organizations using Cisco ASR 9000 routers in critical network paths. The main risk is outage duration and customer impact if a router stops forwarding traffic and requires restart.
Technical view
Cisco IOS XR on ASR 9000 routers can mishandle buffer resources during slow-path, software-switched packet processing. Specific Layer 2 or Layer 3 PDUs can exhaust buffers, causing denial of service. CVSS 3.1 is 8.6 with network access, low complexity, no privileges, and high availability impact.
Likely exposure
Exposure appears limited to Cisco ASR 9000 Series Aggregation Services Routers running Cisco IOS XR Software where traffic can reach affected ingress processing paths, especially punted software-switching conditions.
Exploitation context
The bundle does not show CISA KEV listing or cited evidence of active exploitation. The vulnerability is remotely reachable and unauthenticated, so exposed routing infrastructure should still be treated as urgent.
Researcher notes
This is CWE-404 improper resource allocation with availability-only impact. Evidence in the bundle supports remote unauthenticated DoS, not compromise or code execution. Product/version granularity is incomplete here, so rely on Cisco’s advisory for release-level determination.
Mitigation direction
- Review Cisco’s advisory for affected releases, fixed software, and any interim guidance.
- Prioritize remediation on internet-facing or untrusted-edge ASR 9000 routers.
- Reduce unnecessary exposure to untrusted Layer 2 or Layer 3 traffic paths.
- Ensure restart and failover procedures are ready for affected routing devices.
- Monitor for buffer exhaustion, forwarding loss, and unexpected router unavailability.
Validation and detection
- Inventory Cisco ASR 9000 routers and their IOS XR Software versions.
- Compare deployed versions and models against Cisco’s advisory.
- Identify interfaces receiving untrusted or high-volume Layer 2 or Layer 3 traffic.
- Check operations logs for buffer exhaustion or forwarding-plane disruption indicators.
- Confirm redundancy and maintenance windows before remediation or restart activities.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-404: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2020-26070 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H3.94Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
8.6HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:H
Source materials
- CVE List V5 sourceCVE List V5
- 20201110 Cisco IOS XR Software for Cisco ASR 9000 Series Aggregation Services Routers Slow Path Forwarding Denial of Service VulnerabilityCVE reference · vendor-advisory, x_refsource_CISCO
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Resource Shutdown or Release
Improper Resource Shutdown or Release represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.