High severity7.5NVD Advisory· Published Sep 6, 2023· Updated Jun 17, 2026
CVE-2023-4809
CVE-2023-4809
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.
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LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
13cpe:2.3:o:freebsd:freebsd:*:*:*:*:*:*:*:*+ 11 more
- cpe:2.3:o:freebsd:freebsd:*:*:*:*:*:*:*:*range: <12.4
- cpe:2.3:o:freebsd:freebsd:12.4:-:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:12.4:p1:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:12.4:p2:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:12.4:p3:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:12.4:p4:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:12.4:rc2-p1:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:12.4:rc2-p2:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:13.2:-:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:13.2:p1:*:*:*:*:*:*
- cpe:2.3:o:freebsd:freebsd:13.2:p2:*:*:*:*:*:*
- (no CPE)range: 13.2-RELEASE
Patches
Vulnerability mechanics
References
5- www.openwall.com/lists/oss-security/2023/09/08/5nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2023/09/08/6nvdMailing ListThird Party Advisory
- www.openwall.com/lists/oss-security/2023/09/08/7nvdMailing ListThird Party Advisory
- security.freebsd.org/advisories/FreeBSD-SA-23:10.pf.ascnvdVendor Advisory
- security.netapp.com/advisory/ntap-20231221-0009/nvd
News mentions
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