CVE-2026-4748
moderate-risk
Published 2026-04-01
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.
Do I need to act?
-
0.04% chance of exploitation
EPSS score — low exploit probability
-
Not on CISA KEV list
No confirmed active exploitation reported to CISA
?
Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10
High
NETWORK
/ LOW complexity
Affected Products (18)
Affected Vendors
References (1)
Vendor Advisory
https://security.freebsd.org/advisories/FreeBSD-SA-26:09.pf.asc
45
/ 100
moderate-risk
Severity
26/34 · High
Exploitability
0/34 · Minimal
Exposure
19/34 · Moderate