CVE-2026-4748CWE-1023CWE-480CWE-754

pf silently ignores certain rules

High · published April 1, 2026

CVSS v3.1
7.5
EPSS
0%
Percentile
34.8
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.5 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00416 · 34.8th percentile
Weaknesses
CWE-1023 · Incomplete Comparison with Missing Factors; CWE-480 · Use of Incorrect Operator; CWE-754 · Improper Check for Unusual or Exceptional Conditions
Published
2026-04-01T06:18Z
EPSS history
Timeline
  • 01 APR 06:18Z
    pf silently ignores certain rules
    cvelistv5