Security readout for executives and security teams
This flaw can let traffic pass through a Cisco ASR 9000 router even when an access control list should block it. It affects specific IOS XR configurations involving TCP flag ACL inspection and 3-tuple Cisco Express Forwarding load balancing. The business risk is policy bypass at network boundaries, not router takeover. Exposure appears limited to Cisco ASR 9000 Series Aggregation Services Routers running IOS XR 5.1.1 or later before fixed releases, with the affected ACL and load-balancing configuration present. Organizations without ASR 9000, without IOS XR in the affected range, or without that configuration are less likely exposed. Prioritize remediation where ASR 9000 routers enforce important segmentation or perimeter policy. The severity is moderate, but the impact can matter if business controls rely on ACLs to block restricted traffic paths. Mitigation focus: Upgrade affected devices to IOS XR 6.5.2, 6.6.1, or later fixed releases.; Apply Cisco-documented workarounds if immediate upgrade is not feasible.; Prioritize routers enforcing boundary, partner, or sensitive segmentation ACLs..
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
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ATT&CK lookup starting points
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CWE-284: Authorization and privilege behavior lookup
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Open ATT&CK lookupCVE-2019-1686 mapping review
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Open ATT&CK lookup- Severity
- Medium
- CVSS
- 5.8 (3.0)
- Known Exploited
- No
- Published
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
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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:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N3.91.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.0 score
5.8MediumVector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- 20190417 Cisco ASR 9000 Series Aggregation Services Routers ACL Bypass 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 Access Control
Improper Access Control represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.