It should be labeled as a ‘sev-medium’ like  issue 813814  and others.

We've been pretty inconsistent with the severity for this type of spoof. Medium and Low are both used fairly frequently. Since that bug is fairly recent I'll up this to medium for consistency, but I'll defer to anyone who deals with this type of issue more often if they want to change it again.

Another example - http://xn--12-6kc4a0ah.com (hoa123.com is also a top-10K site).

Thank you for the report. 

Curiously, U+0417 (З) is in the Unicode confusables list, but its lowercase counterpart U+0437 (з) is not.
The same is true of U+04E0 (Ӡ) and U+04E1 (ӡ). 

https://unicode.org/cldr/utility/confusables.jsp?a=%D0%B7%D3%A1&r=None found more:

U+025C (ɜ), U+1D08 (ᴈ)
U+021D(ȝ)	U+0292(ʒ)	U+04E1(ӡ)	U+10F3(ჳ)	
U+2CCD(ⳍ)	U+A76B(ꝫ). 

U+2CCD is Coptic that is not allowed. Others have to added to confusable map. 
 

Well,  [[\u025c\u1d08\u021d\u0292\u04e1\u10f3\u2ccd\ua76b] & [:IdentifierStatus=Allowed:]]  has only one element, U+04E1.  
( https://goo.gl/p1uKHj )

So, for this bug, U+0437 and U+04E1 have to be mapped to 3. 

'1' (digit 1) will be a can of worms.  ( bug 817247  )

$ egrep '^[0-9]{2,}\.' alexa_domains.list | wc -l
50

$ egrep '[0-9]' alexa_domains.list  | wc -l
663

$ egrep '[0-9]{2,}' alexa_domains.list | wc -l
345 

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/de9acc5cb3527da9173f01973d849bd47f91a9fd

commit de9acc5cb3527da9173f01973d849bd47f91a9fd
Author: Jungshik Shin <jshin@chromium.org>
Date: Fri Mar 16 02:25:57 2018

Add more to confusables list

U+04FB (ӻ) to f
U+050F (ԏ) to t
U+050B (ԋ) and U+0527 (ԧ) to h
U+0437(з) and U+04E1(ӡ) to 3

Add tests for the above entries and tests for ASCII-digit spoofing.

Bug:  816769 , 820068 
Test: components_unittests --gtest_filter=*IDN*
Change-Id: I6cd0a7e97cd0ec2df522ce30f632acfd7b78eee2
Reviewed-on: https://chromium-review.googlesource.com/962875
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Commit-Position: refs/heads/master@{#543600}
[modify] https://crrev.com/de9acc5cb3527da9173f01973d849bd47f91a9fd/components/url_formatter/idn_spoof_checker.cc
[modify] https://crrev.com/de9acc5cb3527da9173f01973d849bd47f91a9fd/components/url_formatter/top_domains/test_domains.list
[modify] https://crrev.com/de9acc5cb3527da9173f01973d849bd47f91a9fd/components/url_formatter/top_domains/test_skeletons.gperf
[modify] https://crrev.com/de9acc5cb3527da9173f01973d849bd47f91a9fd/components/url_formatter/url_formatter_unittest.cc

Verified today on 67.0.3373.0, ԝзѕснооӏѕ.com is shown as expected. Thanks Jungshik as ever!

Thank you for verifying the fix and reporting the bug. 

This bug requires manual review: Less than 24 days to go before AppStore submit on M66
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), josafat@(ChromeOS), abdulsyed@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Merge approved - branch:3359

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/a0909838fdd22cf3de12f2e6f896ac14d82257d0

commit a0909838fdd22cf3de12f2e6f896ac14d82257d0
Author: Jungshik Shin <jshin@chromium.org>
Date: Tue Mar 20 20:50:45 2018

[M66 branch] Add more to confusables list

U+04FB (ӻ) to f
U+050F (ԏ) to t
U+050B (ԋ) and U+0527 (ԧ) to h
U+0437(з) and U+04E1(ӡ) to 3

Add tests for the above entries and tests for ASCII-digit spoofing.

Bug:  816769 , 820068 
Test: components_unittests --gtest_filter=*IDN*
Change-Id: I6cd0a7e97cd0ec2df522ce30f632acfd7b78eee2
Reviewed-on: https://chromium-review.googlesource.com/962875
Reviewed-by: Peter Kasting <pkasting@chromium.org>
Commit-Queue: Peter Kasting <pkasting@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#543600}(cherry picked from commit de9acc5cb3527da9173f01973d849bd47f91a9fd)
Reviewed-on: https://chromium-review.googlesource.com/971769
Reviewed-by: Jungshik Shin <jshin@chromium.org>
Cr-Commit-Position: refs/branch-heads/3359@{#355}
Cr-Branched-From: 66afc5e5d10127546cc4b98b9117aff588b5e66b-refs/heads/master@{#540276}
[modify] https://crrev.com/a0909838fdd22cf3de12f2e6f896ac14d82257d0/components/url_formatter/idn_spoof_checker.cc
[modify] https://crrev.com/a0909838fdd22cf3de12f2e6f896ac14d82257d0/components/url_formatter/top_domains/test_domains.list
[modify] https://crrev.com/a0909838fdd22cf3de12f2e6f896ac14d82257d0/components/url_formatter/top_domains/test_skeletons.gperf
[modify] https://crrev.com/a0909838fdd22cf3de12f2e6f896ac14d82257d0/components/url_formatter/url_formatter_unittest.cc

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$500 for this report, thanks!

This bug has been closed for more than 14 weeks. Removing security view restrictions.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot