Probably it changed the permissions of the
wp-content directory itself, or one of its subdirectories, in this case, maybe the
plugins folder. You can check that with a ftp client (like FileZilla) or ssh.
Comparing with my installations, the wp-content folder has
0755 permissions, which means it has read, write and execution access for the owner, and read and execution access to the group and others, the files inside
0644 permissions (read, write and no execution access for the owner, and only read permissions for the group and others).
An easy way to make sure all the permissions are correctly is run through ssh:
chmod -R a-x+X wp-content/
That takes out the the execution permission (
-x) for every user (
a) and file inside the folder and its children(
-R) and only add it for the directories (
+X; that need execution permission to be browsed).
If the permissions are all messed up (let's suppose that files doesn't have the 0644 permissions), you can do it by hand or by doing:
chmod -R 0755 wp-content/
Which will make every file have execution permission (I think is a security issue, but will last for a few seconds ;)). And then use the first command, that way all permissions would be "reset"; not very elegant solution, but works.