Linux Linux Kernel
CVE-2026-43329
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.
What this means for your business
- It affects Linux Kernel. It matters if your company, or a supplier that handles your data, runs it.
- An attacker can use it only with access to the machine itself, with an ordinary user login, and without anyone at your company clicking anything.
- FIRST's prediction model gives it a 0.1% chance of attack attempts being seen in the next 30 days, ranking above 3% of all known flaws.
What to do
- 1Check whether your company or your suppliers run Linux Kernel, and which version. The affected versions are listed further down this page.
- 2If you do, apply the vendor's fix. A patch or vendor advisory has been published.
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Scoring
- CVSS
- 7.8 (v3.1)
- Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H- Weakness
- CWE-770
- Assigned by
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Dates
- Published
- 2026-05-08
- Last modified
- 2026-09-15
- Sources
- NVD
Affected products
- Linux Linux Kernel5.5 - 5.15.203, 5.16 - 6.1.168, 6.2 - 6.6.134, 6.7 - 6.12.81, 6.13 - 6.18.22, 6.19 - 6.19.12, 7.0
As listed in the NVD configuration data. Not a statement about your estate.
References
- https://git.kernel.org/stable/c/504c9456699dcf4d15195ef34a0fa94a80bfc877
- https://git.kernel.org/stable/c/5382bb03e9c33b089d60788478b922a2dca284cc
- https://git.kernel.org/stable/c/57c78bd2e2dd08897acd35b2bf8bcef322e36f5e
- https://git.kernel.org/stable/c/76522fcdbc3a02b568f5d957f7e66fc194abb893
- https://git.kernel.org/stable/c/879959a7a2be814dd57568655eafa3d8f4d0309e
- https://git.kernel.org/stable/c/ead66c77303f760f6c30be96e2e20d5a77cef614
- https://git.kernel.org/stable/c/fe9018d3e94329f1951b00805a8640bc06f56ead
- https://access.redhat.com/errata/RHSA-2026:23329
- https://access.redhat.com/errata/RHSA-2026:26427
- https://access.redhat.com/errata/RHSA-2026:26428
- https://access.redhat.com/errata/RHSA-2026:27713
- https://access.redhat.com/errata/RHSA-2026:30848
- https://access.redhat.com/errata/RHSA-2026:33215
- https://access.redhat.com/errata/RHSA-2026:33899
- https://access.redhat.com/errata/RHSA-2026:33900