Undefined index after updating core to 7.24

Yesterday I updated one of my sites to 7.24. All went well until I ran cron and got this error: Notice: Undefined index: version_major in update_calculate_project_update_status(). It's from /modules/update/update.compare.inc and I think it relates to the elFinder module. On the Available Updates page, elFinder is now flagged with "No available releases found," and when I disable that module the undefined index error goes away.
Any suggestions on resolving the error will be appreciated. I have about 12 other sites that now need updating, but I don't want to do it until I get this figured out.