Release ASUS RT-AC86U Firmware version 3.0.0.4.386_52294 (2025/10/28)

[fruitcornbread]

Version 3.0.0.4.386_52294
66.52 MB
2025/10/28

- Enhanced system stability.
- Enhanced input validation and refactored legacy string handling routines to ensure robust memory management.
- Mitigated security risks in AiCloud service by enforcing strict credential verification, implementing robust file path validation, and hardening command execution logic to prevent unauthorized access and manipulation of system resources.
- Implemented comprehensive validation and expanded command filtering in the web history API.
- Fixed a privilege escalation vector in the IFTTT token exchange mechanism
- Strengthened input validation and directory handling in the VPN configuration upload interface.
- Fixed an issue that allowed certain user settings to be bypassed, improving overall user control and protection.

ZIP SHA-256 : 6107D58AD49C767B64A69B125E20349C21A28A4729E67422EF5AC179688D7C32
FW SHA-256 : e04142da1d2a3ea90cded26b1d4047e9bb593c162c3ea17be47b150dd6a7e1ae

Download: https://dlcdnets.asus.com/pub/ASUS/wireless/RT-AC86U/FW_RT-AC86U_300438652294.zip?model=RT-AC86U

RT-AC86U｜WiFi Routers｜ASUS Global

ASUS has a range of wireless routers suitable for every purpose. Whether it's for your home, for business trips, or for any other need or environment, there's an ASUS router for you.

www.asus.com

 

[visortgw]

Apparently not EOL, yet...

 

[visortgw]

Download Page (link above expired).

 

[heysoundude]

Apparently not EOL, yet...

well, why would they do that? these are still mostly chugging along happily.

In my case I've made it a switch on my network by disabling the radios in AP mode since my AX88Pro is more than adequate wirelessly. It sits on the opposite side of the house from the RT-N66u doing exactly the same thing in the same way for about twice as long. (I was also rather amused/surprised to see how recently the last update for THAT was released!)

I've been pondering their ends-of-life functionality-wise, and considering their presumed eventual replacements, but upgrading to 2.5GHz is still a little spendy, even if I buy on AliExpress. I mean, they may be ancient by certain standards, but they're still packet pushing champs. I can't justify paying to upgrade with a 120/20Mbps ISP line speed...but the competition is heating up for me to change over to 1Gbps/300Mbps, so...if the monthly price for that drops below what I'm paying, or someone brings glass to the house for the same money...

 

[visortgw]

well, why would they do that? these are still mostly chugging along happily.

In my case I've made it a switch on my network by disabling the radios in AP mode since my AX88Pro is more than adequate wirelessly. It sits on the opposite side of the house from the RT-N66u doing exactly the same thing in the same way for about twice as long. (I was also rather amused/surprised to see how recently the last update for THAT was released!)

I've been pondering their ends-of-life functionality-wise, and considering their presumed eventual replacements, but upgrading to 2.5GHz is still a little spendy, even if I buy on AliExpress. I mean, they may be ancient by certain standards, but they're still packet pushing champs. I can't justify paying to upgrade with a 120/20Mbps ISP line speed...but the competition is heating up for me to change over to 1Gbps/300Mbps, so...if the monthly price for that drops below what I'm paying, or someone brings glass to the house for the same money...

EOL reached about a year or so ago...

 

[Tech9]

these are still mostly chugging along happily

Mass update of EoL models means critical vulnerability discovered.

 

[fruitcornbread]

Download Page (link above expired).

The direct download link in the first post works if you paste it in a browser for some reason.

 

[heysoundude]

Mass update of EoL models means critical vulnerability discovered.

Ignorance is bliss? ;-D

 

[Oniiz86]

Implemented comprehensive validation and expanded command filtering in the web history API.G1

@fruitcornbread I was just wondering is that simply a typo as that "G1" is not present in the firmware notes?

 

[jksmurf]

@fruitcornbread I was just wondering is that simply a typo as that "G1" is not present in the firmware notes?

- Implemented comprehensive validation and expanded command filtering in the web history API.G1

I'd say that was a fairly safe bet as a typo... even the "supportonly" link shows the same.
[not sure how independent it is though, might be just a mapped path]

https://www.asus.com/supportonly/rt-ac86u/helpdesk_bios?model2Name=RT-AC86U

 

[fruitcornbread]

@fruitcornbread I was just wondering is that simply a typo as that "G1" is not present in the firmware notes?

Whoops bad copy and paste job. Nice catch. Edited.

 

[fisherman]

Having now tried numerous times unsuccessfully to update from 51967 (tried both iOS app and remote login) I hafta ask if anyone else has had trouble with this.

Yes I'm remote from it and in the absence of an idea here I will have to try in person in about two weeks.

 

[maxbraketorque]

Mass update of EoL models means critical vulnerability discovered.

Looks like other updates were made as well. I guess its easier to apply all updates than selectively apply a fix for a vulnerability.

 

[Tech9]

Unfortunately, I don't have a single person around me with surviving RT-AC86U model. It was very popular, I used to recommend it for excellent price/performance ratio at some point, but even the ones we thought are good started showing hardware issues and were long time ago replaced. No idea if this firmware upgrade is good or bad, nothing to test it on.

 

[OzarkEdge]

Unfortunately, I don't have a single person around me with surviving RT-AC86U model. It was very popular, I used to recommend it for excellent price/performance ratio at some point, but even the ones we thought are good started showing hardware issues and were long time ago replaced. No idea if this firmware upgrade is good or bad, nothing to test it on.

When 3 AC86Us died on me, I retired my still working 4th AC86U... too much trouble.

OE

 

[Tech9]

Planning upgrade to something more reliable and supported is my recommendation as well.

 

[Ameenhuus]

I bought this router in Hong Kong in 2017. I've been using it for years when I'm on vacation, staying in hotels, etc. It still works perfectly, and I never had any problems with it when I used it at home for the first few years.

 

[fisherman]

Unfortunately, I don't have a single person around me with surviving RT-AC86U model. It was very popular, I used to recommend it for excellent price/performance ratio at some point, but even the ones we thought are good started showing hardware issues and were long time ago replaced. No idea if this firmware upgrade is good or bad, nothing to test it on.

Yeah I read here early on about hardware problems and so long as mine have worked fine I've not seen a need to spend the $$ on new.

An unhappy side issue with my failed update attempts has been that all my custom client icons & names got blown-away, damn.

 

[Tech9]

I've not seen a need to spend the $$ on new

This need happens instantly with RT-AC86U. Most die after internal voltage regulator failure without any prior trouble warnings. You get Power and half lit LAN4 LED. Replace before it happens. The chance of failure is higher than any other ASUS model.

 

[jksmurf]

An unhappy side issue with my failed update attempts has been that all my custom client icons & names got blown-away, damn.

There are a number of relatively simple ways to save these, if you’re going to be doing this a lot, it’s a great thing to learn how to save them, so you can just put them back and hey presto all works. Unfortunately (keeping to thread subject) you might have to install Merlin FW, I’m not sure if the methods work on stock FW (SSH might).

Many threads on this (here’s one) but in order of ease of use (IMO):

1. Install YazDHCP if your FW supports it.
2. Drag and drop custom_clientlist and dhcp_staticlist from/to /jffs/nvram/.
3. Same as 2 but using command line export/import of file contents via SSH.

Saved me hours of reconfiguration, especially when your lists have numerous devices. Custom icons are trickier, although YazDHCP does this well IIRC.

[EDIT1] There were some concerns a while ago that copying the files did not work but RMerlin confirmed reasonably recently this could still be done.

[EDIT2] If you want to have some fun with a custom_clientlist generator I cobbled together in Excel, have a wee look at this post.