VULNERABILITY INTELLIGENCE

CVE-2023-4809

CVSS score7.5 HIGH
EPSS probability0.80%
CISA KEVNot currently listed
Published2023-09-06
Last modified2026-06-17
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

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.

Weakness classification

  • secteam@freebsd.org: CWE-167
  • nvd@nist.gov: NVD-CWE-Other

Primary references