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CVE-2021-22161

MEDIUMCVSS 6.5/10EPSS 0.52%

Last modified

CVE-2021-22161 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. In OpenWrt 19.07.x before 19.07.7, 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 0.52% chance of exploitation in the next 30 days.

Description

In OpenWrt 19.07.x before 19.07.7, 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. This affects the netifd and odhcp6c packages.

Metrics

CVSS 3.1
6.5/10

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

EPSS Probability
0.52%

40.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
OpenwrtOpenwrt>= 19.07.0, <= 19.07.6

References

Timeline

Published
Last Modified
Status
Modified

Frequently Asked Questions

What is CVE-2021-22161?
In OpenWrt 19.07.x before 19.07.7, 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. This affects the netifd and odhcp6c packages.
How severe is CVE-2021-22161?
CVE-2021-22161 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.52% probability of exploitation in the next 30 days.
How do I fix CVE-2021-22161?
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-2021-22161?

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

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Source: NVD / NIST