Vulnerability Monitor

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CVE-2019-1686


A vulnerability in the TCP flags inspection feature for access control lists (ACLs) on Cisco ASR 9000 Series Aggregation Services Routers could allow an unauthenticated, remote attacker to bypass protection offered by a configured ACL on an affected device. The vulnerability is due to incorrect processing of the ACL applied to an interface of an affected device when Cisco Express Forwarding load balancing using the 3-tuple hash algorithm is enabled. An attacker could exploit this vulnerability by sending traffic through an affected device that should otherwise be denied by the configured ACL. An exploit could allow the attacker to bypass protection offered by a configured ACL on the affected device. There are workarounds that address this vulnerability. Affected Cisco IOS XR versions are: Cisco IOS XR Software Release 5.1.1 and later till first fixed. First Fixed Releases: 6.5.2 and later, 6.6.1 and later.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 8.6, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts integrity (unauthorized modifications), for affected systems. Impacting 11 products from cisco, from cisco, from cisco and 8 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

First disclosed in 2019, this vulnerability was reported during a period defined by widespread IoT adoption challenges, mobile security concerns, and the emergence of advanced persistent threat (APT) techniques. Contemporary mitigation strategies focused on secure development practices and third-party component vetting.


Published

2019-04-17T22:29:00.360

Last Modified

2024-11-21T04:37:05.900

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 8.6 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:P/A:N

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: PARTIAL
  • Availability Impact: NONE
Exploitability Score

10.0

Impact Score

2.9

Weaknesses
  • Type: Secondary
    CWE-284
  • Type: Primary
    NVD-CWE-Other

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Operating System cisco ios_xr < 6.5.2 Yes
Operating System cisco ios_xr < 6.6.1 Yes
Hardware cisco asr_9000v - No
Hardware cisco asr_9001 - No
Hardware cisco asr_9006 - No
Hardware cisco asr_9010 - No
Hardware cisco asr_9901 - No
Hardware cisco asr_9904 - No
Hardware cisco asr_9906 - No
Hardware cisco asr_9910 - No
Hardware cisco asr_9912 - No
Hardware cisco asr_9922 - No

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For cisco's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.