Last modified: 2012-12-10 20:52:21 UTC

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Bug 14600 - Illegal Unicode characters are allowed in pages
Illegal Unicode characters are allowed in pages
Status: NEW
Product: MediaWiki
Classification: Unclassified
Page editing (Other open bugs)
All All
: Low normal (vote)
: ---
Assigned To: Nobody - You can work on this!
Depends on:
  Show dependency treegraph
Reported: 2008-06-20 14:39 UTC by Amir E. Aharoni
Modified: 2012-12-10 20:52 UTC (History)
0 users

See Also:
Web browser: ---
Mobile Platform: ---
Assignee Huggle Beta Tester: ---


Description Amir E. Aharoni 2008-06-20 14:39:18 UTC
Take a good look at this diff from the Russian Wikipedia:

What was fixed is four instances of the Unicode character FDD3.

I stumbled upon it when i ran a Perl script that analyzed a dump of the Russian Wikipedia. I ran several pattern matches on every page and on this page the Perl regular expression engine issued this warning: "Unicode character is illegal" (see ). The code chart in which this character appears indeed says this: "These codes are intended for process-internal uses, but are not permitted for interchange." (Search for FDD3 here: )

My Unicode expertise ends here. I don't know what exactly are those illegal characters. I can guess that characters that have the Noncharacter_Code_Point property are illegal, and maybe there are more. I also don't know what is the exact damage that these characters cause if saved in the MediaWiki database, but i can guess that it may cause interoperability troubles with external tools - browsers, bots, search engines, future versions of the database engine etc. It may also cause security breaches. So i suppose that there is a warning sign here and most probably it shouldn't be possible to save pages that include such characters.
Comment 1 Brion Vibber 2008-06-20 22:28:36 UTC
They're not technically illegal, but perhaps should be excluded as they wouldn't be useful.

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