CVE-2019-1686: cisco cisco ios xr software Improper Access Control
Vulnerability summary
CVE-2019-1686 is a high (CVSS 8.6) Improper Access Control vulnerability in cisco cisco ios xr software. EPSS estimates a 1.59% chance of exploitation in the next 30 days, higher than 75.4% of scored vulnerabilities.
Timeline
- 17-04-2019PublishedVulnerability first disclosed.
- 19-11-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
4 scores · 2 sources · 3 versions- NVDNIST5.8MediumCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
EPSS trend
Probability
1.59%
Chance of exploitation in the next 30 days
Percentile
75%
Versus all other CVEs
30-day change
0.00 pp
From 1.59% on 22-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Cisco2 products
- cisco ios xr software≥ unspecified, < 6.5.2 | ≥ unspecified, < 6.6.1
- ios_xr≥ 5.1.1, < 6.5.2 | ≥ 6.5.3, < 6.6.1
1 vendor · 2 products
References
2 links- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-20190417-iosxraclVendor AdvisoryX Refsource CISCO