CVE-2023-4809

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.

• CWE-167

• http://www.openwall.com/lists/oss-security/2023/09/08/5Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/09/08/6Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/09/08/7Mailing List, Third Party Advisory
• https://security.FreeBSD.org/advisories/FreeBSD-SA-23:10.pf.ascVendor Advisory
• https://security.netapp.com/advisory/ntap-20231221-0009/
• http://www.openwall.com/lists/oss-security/2023/09/08/5Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/09/08/6Mailing List, Third Party Advisory
• http://www.openwall.com/lists/oss-security/2023/09/08/7Mailing List, Third Party Advisory
• https://security.FreeBSD.org/advisories/FreeBSD-SA-23:10.pf.ascVendor Advisory
• https://security.netapp.com/advisory/ntap-20231221-0009/

Published

Sep 6, 2023

Last Modified

Jun 17, 2026

Status

Modified