CVE-2026-4748: high-severity vulnerability in FreeBSD
pf silently ignores certain rules
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 7.5epss 0.3%
A regression in the way hashes were calculated caused rules containing the address range syntax (x.x.x.x - y.y.y.y) that only differ in the address range(s) involved to be silently dropped as duplicates. Only the first of such rules is actually loaded into pf. Ranges expressed using the address[/mask-bits] syntax were not affected.
Some keywords representing actions taken on a packet-matching rule, such as 'log', 'return tll', or 'dnpipe', may suffer from the same issue. It is unlikely that users have such configurations, as these rules would always be redundant.
Affected rules are silently ignored, which can lead to unexpected behaviour including over- and underblocking.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Affected products
FreeBSD · FreeBSDRelated CVEs — FreeBSD
In the same product, most dangerous first.