CVE-2026-43329
netfilter: flowtable: strictly check for maximum number of actions
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.
INFO
Published Date :
May 8, 2026, 2:16 p.m.
Last Modified :
May 8, 2026, 2:16 p.m.
Remotely Exploit :
No
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Solution
- Update flow_action_entry_next() calls to strictly check action limits.
- Increase maximum actions per flow from 16 to 24.
References to Advisories, Solutions, and Tools
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CVE-2026-43329.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-43329 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-43329
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
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Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
May. 08, 2026
Action Type Old Value New Value Added 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. Added Reference https://git.kernel.org/stable/c/504c9456699dcf4d15195ef34a0fa94a80bfc877 Added Reference https://git.kernel.org/stable/c/5382bb03e9c33b089d60788478b922a2dca284cc Added Reference https://git.kernel.org/stable/c/57c78bd2e2dd08897acd35b2bf8bcef322e36f5e Added Reference https://git.kernel.org/stable/c/76522fcdbc3a02b568f5d957f7e66fc194abb893 Added Reference https://git.kernel.org/stable/c/879959a7a2be814dd57568655eafa3d8f4d0309e Added Reference https://git.kernel.org/stable/c/ead66c77303f760f6c30be96e2e20d5a77cef614 Added Reference https://git.kernel.org/stable/c/fe9018d3e94329f1951b00805a8640bc06f56ead