XSS when $wgShowExceptionDetails = false and browser sends non-standard url escaping (CVE-2017-8808).
Reflected File Download from api.php (CVE-2017-8809).
On private wikis, login form shouldn't distinguish between login failure due to bad username and bad password (CVE-2017-8810).
It's possible to mangle HTML via raw message parameter expansion (CVE-2017-8811).
The id attribute on headlines allow raw > (CVE-2017-8812).
Language converter can be tricked into replacing text inside tags by adding a lot of junk after the rule definition (CVE-2017-8814).
Language converter: unsafe attribute injection via glossary rules (CVE-2017-8815).
composer.json has require-dev versions of PHPUnit with known security issues (CVE-2017-9841).
Note that MediaWiki 1.23.x on Mageia 5 is no longer supported. Those using the mediawiki package on Mageia 5 should upgrade to Mageia 6.