CVE-2019-1686 Cisco ASR 9000 Series Aggregation Services Routers ACL Bypass Vulnerability

Medium 5.8 Published 17 Apr 2019 Updated 19 Nov 2024

Remote attackers can bypass ACL protections on Cisco ASR 9000 routers when specific load balancing settings are enabled.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: None listed

What is CVE-2019-1686?

CVE-2019-1686 is a medium-severity vulnerability in Cisco Ios Xr, published on 17 Apr 2019. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official 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.

Weakness: CWE-284

Which versions are affected by CVE-2019-1686?

It affects 1 product.

Products include Cisco Ios Xr.

How do I fix CVE-2019-1686?

No fix has been published for CVE-2019-1686 yet. Limit exposure of the affected software until one is available.

Is CVE-2019-1686 being exploited?

There is no known exploitation of CVE-2019-1686 in the wild and no public exploit code.

All Cisco Ios Xr vulnerabilities

Sources

Also known as GHSA-9wr9-3p7g-gc32.