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pf -- IP fragment handling panic


Problem description:

A logic bug in pf's IP fragment cache may result in a packet fragment being inserted twice, violating a kernel invariant.


By sending carefully crafted sequence of IP packet fragments, a remote attacker can cause a system running pf with a ruleset containing a 'scrub fragment crop' or 'scrub fragment drop-ovl' rule to crash.


Do not use 'scrub fragment crop' or 'scrub fragment drop-ovl' rules on systems running pf. In most cases, such rules can be replaced by 'scrub fragment reassemble' rules; see the pf.conf(5) manual page for more details.

Systems which do not use pf, or use pf but do not use the aforementioned rules, are not affected by this issue.



portaudit: pf -- IP fragment handling panic

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If you have found a vulnerability in a FreeBSD port not listed in the database, please contact the FreeBSD Security Officer. Refer to "FreeBSD Security Information" for more information.

Oliver Eikemeier <>