WordPress is pretty accessible out of the box but it does have some significant accessibility flaws. However, a great deal depends upon:
1. The chosen theme – most themes are, sadly, below AA compliance so either choose a theme carefully of be prepared to modify it fairly extensively.
2. The awareness level of blog authors. WP can help authors produce semantic accessible site but it can’t correct inaccessible user input. At the end of the day, it is simply a tool and no more.
On a more positive note, WP has been used to produce some quite stunning and highly accessible sites. https://spanish-portuguese.berkeley.edu/ is one of my favourites. Another is https://lflegal.com/ – which is currently 1 of only 2 officially recognised WCAG 2.0 AAA sites worldwide.
https://accessites.org/site/2008/11/wordpress-and-accessibility/ is an article that specifically looks at WP and accessibility and there are couple of other articles on Accessites that examine and suggest solutions to the shortcomings highlighted in the article.
