CVE-2026-43329

HIGH

netfilter: flowtable: strictly check for maximum number of actions

Title source: cna
STIX 2.1

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: flowtable: strictly check for maximum number of actions The maximum number of flowtable hardware offload actions in IPv6 is: * ethernet mangling (4 payload actions, 2 for each ethernet address) * SNAT (4 payload actions) * DNAT (4 payload actions) * Double VLAN (4 vlan actions, 2 for popping vlan, and 2 for pushing) for QinQ. * Redirect (1 action) Which makes 17, while the maximum is 16. But act_ct supports for tunnels actions too. Note that payload action operates at 32-bit word level, so mangling an IPv6 address takes 4 payload actions. Update flow_action_entry_next() calls to check for the maximum number of supported actions. While at it, rise the maximum number of actions per flow from 16 to 24 so this works fine with IPv6 setups.

Scores

CVSS v3 7.8
EPSS 0.0001
EPSS Percentile 2.6%
Attack Vector LOCAL
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Details

Status published
Products (18)
Linux/Linux < 5.5
Linux/Linux 5.15.203 - 5.15.*
Linux/Linux 5.5
Linux/Linux 6.1.168 - 6.1.*
Linux/Linux 6.12.81 - 6.12.*
Linux/Linux 6.18.22 - 6.18.*
Linux/Linux 6.19.12 - 6.19.*
Linux/Linux 6.6.134 - 6.6.*
Linux/Linux 7.0
Linux/Linux c29f74e0df7a02b8303bcdce93a7c0132d62577a - 504c9456699dcf4d15195ef34a0fa94a80bfc877
... and 8 more
Published May 08, 2026
Tracked Since May 08, 2026