Release Asus RT-AX86 Series Firmware version 3.0.0.4.388_24386 9/1/2025

[iFrogMac]

ASUS RT-AX86 Series(RT-AX86U/RT-AX86S) Firmware version 3.0.0.4.388_24386

Version 3.0.0.4.388_24386

71.53 MB

2025/09/01

SHA-256 ：617E472529D16308D38A804445A555275898FA8A702713E20C257D5831C50C36

Important: After installing this firmware, we strongly recommend performing a factory-default reset to activate every new security adjustment.

Security Enhancements
- Password Policy Upgrade – Minimum 10 characters with at least 1 letter, 1 digit and 1 special symbol, and no consecutive identical characters; hardens defense against brute-force attacks.
- HTTPS on 8443 – Management interface now served over TLS by default.
- UPnP Disabled – Universal Plug and Play starts in the off state for reduced surface exposure.
- AiCloud Authentication Hardening (CWE-287) – Added layered verification.
- Authentication Logic Refactor – Removed redundant code paths for a lean sign-in flow.
- Memory Safety Guard (CWE-476) – Introduced null-reference protections across critical services.
- Enhanced IPsec Parameter Validation – The existing input checks have been hardened.
- Data Exposure Mitigation (CWE-200) – Reinforced controls on sensitive pathways.
- Detailed Audit Trails – Expanded logging within the authentication module.

System Improvements
- Connection Stability – Core algorithms refined for steadier links.
- Scheduling Accuracy – Timed tasks execute reliably under PPPoE, PPTP and L2TP WAN modes.
- Client List Maintenance – Resolved an issue that prevented offline devices from being removed from the client list.
Download link: https://www.asus.com/us/supportonly/rtax86u/helpdesk_bios/

 

[bennor]

Download link: https://www.asus.com/us/supportonly/rtax86u/helpdesk_bios/

Direct firmware download link: https://dlcdnets.asus.com/pub/ASUS/...X86U_RT_AX86S_300438824386.zip?model=RT-AX86U

 

[iFrogMac]

Direct firmware download link: https://dlcdnets.asus.com/pub/ASUS/...X86U_RT_AX86S_300438824386.zip?model=RT-AX86U

Thanks for providing the direct link. I wasn't sure if it was better to just provide the link to the Asus site, or direct to the firmware, or even both.

 

[kd4e]

For those who use the asuswrt-merlin firmware, is an update likely to be released - really soon, that includes all of this?

 

[bennor]

For those who use the asuswrt-merlin firmware, is an update likely to be released - really soon, that includes all of this?

Only person who knows is the developer, @RMerlin. And they can only do so if Asus provides the GPL's containing the updates to them.

 

[iFrogMac]

Even though I posted this thread, I haven't updated my router yet. I was curious, if I don't do the suggested factory reset that Asus recommends, how many of the new updates will not function as intended? I ask, because according to the list of changes, many of the settings I have made, are the new defaults on the new firmware. Also, if I were to backup my settings and restore on reconfigure, would it be the same as if I didn't factory reset at all?

 

[OzarkEdge]

if I don't do the suggested factory reset that Asus recommends, how many of the new updates will not function as intended?

Assume all of them.

Also, if I were to backup my settings and restore on reconfigure, would it be the same as if I didn't factory reset at all?

Save and restore is for recovering what you had... same model, same firmware, same settings... not for migrating old firmware settings to new firmware.

OE

 

[bennor]

Also, if I were to backup my settings and restore on reconfigure, would it be the same as if I didn't factory reset at all?

This has been asked a number of times with the latest Asus firmware release. Note what RMerlin posted in response in another discussion to the question:

Reloading that config will completely overwrite the changes done by the factory default reset. So you'd be back to the same point as before.

As always, what you chose to do is up to you. As voiced in several other recent Release discussions on the Asus strong suggestion one perform a reset to apply the new security settings; some are choosing not to perform the suggested reset for their own reasons.

 

[SteverinoLA]

I wish there was a way to:

1) export a text list of all the changes to default firmware (so I know exactly what to change after factory default)

2) export and then import my list of device names & icons. I have 67 devices each hand-named with custom icon.

 

[iFrogMac]

This has been asked a number of times with the latest Asus firmware release. Note what RMerlin posted in response in another discussion to the question:

As always, what you chose to do is up to you. As voiced in several other recent Release discussions on the Asus strong suggestion one perform a reset to apply the new security settings; some are choosing not to perform the suggested reset for their own reasons.

I typically do a factory reset on firmware updates. I was mainly curious in this case because the new defaults Asus sets, are already set by me in the settings. I will probably just do a factory reset, and start fresh though. I haven't updated because I am using different router, and put the RT-AX86U away as a backup router in the event I have issues with the one I'm using. I just happened to check the Asus support site this morning to see if there were any firmware updates since nothing has shown up on the forum until today.