VulnerabilityDeferred

CVE-2024-6640

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.

MEDIUM 6.3EPSS 0.46%

Does this matter?

Lower severity and a low EPSS score (0.46%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 3.1: 6.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L
EPSS: 0.46% probability · 39th percentile
CISA KEV: Not listed
Weakness: CWE-276
Source: secteam@freebsd.org

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.