CVE-2024-6640

pf incorrectly matches different ICMPv6 states in the state table

Description

In ICMPv6 Neighbor Discovery (ND), the ID is always 0. When pf is configured to allow ND and block incoming Echo Requests, a crafted Echo Request packet after a Neighbor Solicitation (NS) can trigger an Echo Reply. The packet has to come from the same host as the NS and have a zero as identifier to match the state created by the Neighbor Discovery and allow replies to be generated. ICMPv6 packets with identifier value of zero bypass firewall rules written on the assumption that the incoming packets are going to create a state in the state table.

Category

6.3
CVSS
Severity: Medium
CVSS 3.1 •
EPSS 0.09%
Vendor Advisory freebsd.org
Affected: FreeBSD FreeBSD
Published at:
Updated at:

References

Link Tags
https://security.freebsd.org/advisories/FreeBSD-SA-24:05.pf.asc vendor advisory
https://security.netapp.com/advisory/ntap-20240816-0008/

Frequently Asked Questions

What is the severity of CVE-2024-6640?
CVE-2024-6640 has been scored as a medium severity vulnerability.
How to fix CVE-2024-6640?
To fix CVE-2024-6640, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2024-6640 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2024-6640 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2024-6640?
CVE-2024-6640 affects FreeBSD FreeBSD.
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