CVE-2023-4809 (published 2023-09-06T19:26:45.833Z)
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.


Affected products: Vendor: FreeBSD
Product: FreeBSD
Versions: 13.2-RELEASE, 12.4-RELEASE