CVE-2024-6640 json
pf incorrectly matches different ICMPv6 states in the state table
published 2024-08-11 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-47675
- cvss
- 6.3
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.5%
- EPSS 0.5% chance of exploitation in 30 days, percentile 40%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- FreeBSD FreeBSD p3, p5, p9
CISA SSVC
- Exploitation
- none
- Automatable
- no
- Technical impact
- partial
- Assessed
- 2 y ago
Exploit prediction
0.46% chance of exploitation in the next 30 days, higher than 40% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CISA ADP | 3.1 | 6.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L |
| CNA | 3.1 | 6.3 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:L |
Affected products
- FreeBSD FreeBSD
Classification
- Weakness
-
- CWE-276 Incorrect Default Permissions
References
Sources
- CVE List CVE-2024-6640
- NVD CVE-2024-6640
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