CVE-2021-23270

Name: CVE-2021-23270
Creator: NVD / NIST
Published: 2021-04-12T19:15:14.517+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 1.03%

Last modified Jun 17, 2026

CVE-2021-23270 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. In Gargoyle OS 1.12.0, when IPv6 is used, a routing loop can occur that generates excessive network traffic between an affected device and its upstream ISP's router. This occurs when a link prefix route points to a point-to-point link, a destination IPv6 address belongs to the prefix and is not a local IPv6 address, and a router advertisement is received with at least one global unique IPv6 prefix for which the on-link flag is set.. EPSS estimates a 1.03% chance of exploitation in the next 30 days.

Description

In Gargoyle OS 1.12.0, when IPv6 is used, a routing loop can occur that generates excessive network traffic between an affected device and its upstream ISP's router. This occurs when a link prefix route points to a point-to-point link, a destination IPv6 address belongs to the prefix and is not a local IPv6 address, and a router advertisement is received with at least one global unique IPv6 prefix for which the on-link flag is set.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

1.03%

59.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-834

Affected Software

Vendor	Product	Versions
Gargoyle-Router	Gargoyle	1.12.0

References

https://github.com/ericpaulbishop/gargoyle/commit/24afe944a6ffff53d84a748384e276a4e95912ecPatch, Third Party Advisory
https://github.com/ericpaulbishop/gargoyle/commit/24afe944a6ffff53d84a748384e276a4e95912ecPatch, Third Party Advisory

Timeline

Published: Apr 12, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-23270?

How severe is CVE-2021-23270?

CVE-2021-23270 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 1.03% probability of exploitation in the next 30 days.

How do I fix CVE-2021-23270?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-23270?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST