CVE-2023-4809 (freebsd)

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 …

cve extension freebsd headers ipv6 packet payload