In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is.




As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.
Advisories

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Fixes

Solution

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Workaround

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History

Sun, 13 Jul 2025 13:45:00 +0000

Type Values Removed Values Added
Metrics epss

{'score': 0.003}

epss

{'score': 0.00272}


Thu, 13 Feb 2025 17:30:00 +0000

Type Values Removed Values Added
Description In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is. As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host. In pf packet processing with a 'scrub fragment reassemble' rule, a packet containing multiple IPv6 fragment headers would be reassembled, and then immediately processed. That is, a packet with multiple fragment extension headers would not be recognized as the correct ultimate payload. Instead a packet with multiple IPv6 fragment headers would unexpectedly be interpreted as a fragmented packet, rather than as whatever the real payload is. As a result, IPv6 fragments may bypass pf firewall rules written on the assumption all fragments have been reassembled and, as a result, be forwarded or processed by the host.

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cve-icon MITRE

Status: PUBLISHED

Assigner: freebsd

Published:

Updated: 2025-02-13T17:18:10.982Z

Reserved: 2023-09-06T17:11:30.349Z

Link: CVE-2023-4809

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Modified

Published: 2023-09-06T20:15:08.080

Modified: 2025-02-13T18:15:47.657

Link: CVE-2023-4809

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses