ENKR

RT-AC66U B1

Ended

Security updates ended May 2026

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Dates and sources

Dates and sources

Calculated ASUS’s firmware page marks this model as end-of-life without a date, so I use the release date of its final firmware (May 12, 2026).

Key dates

Release
By August 2018 at the latest
The maker gives no launch date. This is the month of the first update: the launch was in it or before.
Last update
May 12, 2026 · version 3.0.0.4.386_52102
End of support
May 12, 2026 · calculated by us from the maker’s data
How I calculated it: ASUS’s firmware page for this model says it reached end of life and its firmware will no longer be updated, next to the final firmware 3.0.0.4.386_52102. ASUS gives no separate date, so we use that final firmware’s release date (2026-05-12).
Maker’s end-of-life list
Listed, no date given

Firmware updates

Updates I found on the maker’s pages, from August 2018 to May 2026. I read the notes of 36 of these updates and found security changes in 23.

3.0.0.4.386_52102 Security
3.0.0.4.386_52062 Security, bug fixes, new features or improvements
3.0.0.4.386_52048 Security, new features or improvements
3.0.0.4.386_51733 Security, bug fixes, new features or improvements
3.0.0.4.386_51729 Bug fixes
32 more
3.0.0.4.386_51722 Bug fixes
3.0.0.4.386_51720 Security
3.0.0.4.386_51685 Security, bug fixes · 1 vulnerability ID (opens in a new tab)
3.0.0.4.386_51668 Bug fixes
3.0.0.4.386.51665 Security, bug fixes · 2 vulnerability IDs (opens in a new tab)
3.0.0.4.386.51255 Security, bug fixes, new features or improvements · 5 vulnerability IDs (opens in a new tab)
3.0.0.4.386.49703 Security, new features or improvements · 2 vulnerability IDs (opens in a new tab)
3.0.0.4.386.48262 Security, new features or improvements · 7 vulnerability IDs (opens in a new tab)
3.0.0.4.386.46065 Security, bug fixes, new features or improvements
3.0.0.4.386.45987 Security, bug fixes · 2 vulnerability IDs (opens in a new tab)
22 more
3.0.0.4.386.43129 Security, bug fixes, new features or improvements · 7 vulnerability IDs (opens in a new tab)
3.0.0.4.386.41634 Security, bug fixes, new features or improvements
3.0.0.4.386.40558 New features or improvements
3.0.0.4.385.20852
3.0.0.4.385.20633 Security
3.0.0.4.385.20632 Bug fixes
3.0.0.4.385.20630 Security, new features or improvements · 2 vulnerability IDs (opens in a new tab)
3.0.0.4.385.20585 Bug fixes, new features or improvements
3.0.0.4.385.20490 Bug fixes, new features or improvements
3.0.0.4.385.20433 New features or improvements
12 more
3.0.0.4.385.20253 Security · 1 vulnerability ID (opens in a new tab)
3.0.0.4.385.20252 Bug fixes
3.0.0.4.385.10002 New features or improvements
3.0.0.4.385.10000 Bug fixes
3.0.0.4.384.81351 Security, bug fixes
3.0.0.4.384.81049 Security, bug fixes, new features or improvements
3.0.0.4.384.45717 Security
3.0.0.4.384.45713 Bug fixes
3.0.0.4.384.45708 Security, bug fixes · 2 vulnerability IDs (opens in a new tab)
3.00.4.384.45149 Security, bug fixes, new features or improvements · 8 vulnerability IDs (opens in a new tab)
3.0.0.4.384.32799 Bug fixes
3.0.0.4.384.32738 Security, bug fixes, new features or improvements

Record

  1. Last advisory with a fix: 1 fixed

    ASUS RT-AC66U B1 firmware 3.0.0.4.386_51685 · checked November 13, 2026

  2. as of

    Fixes received: estimated 15

    Each fix below rests partly on our inference, not only on the maker's word. By this estimate, the newest firmware we know for this model has them. Not counted in the other numbers on this page.

    Show the list: estimated fixes

    Basis: The firmware we recorded for this model is on a different version line from the fixed firmware, so we assumed it has the fix because its number or date is later.

Sources

Replacements

Among routers still getting updates

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Until you replace it

  1. Check that firmware 3.0.0.4.386_52102 or later is installed.
  2. Turn off remote (WAN) management, WPS and UPnP.
  3. Change the admin and Wi-Fi passwords.
  4. Check the vendor page in case a final firmware is listed.

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