The WordPress security team has officially forked the long-abandoned SWFUpload project and is strongly encouraging all web developers who use SWFUpload to update.
We strongly suggest you do not use SWFUpload. But if you must, use this fork. You can find it on GitHub at github.com/wordpress/secure-swfupload.
WordPress does not use SWFUpload, but we continue to include it in WordPress core for plugins that have yet to be updated to use Plupload, our upload library of choice. Plupload is written and actively maintained by Moxiecode, the developers of TinyMCE.
We do not condone the use of abandonware. We only wish to make the web a better place by ensuring that developers have access to a secure version of SWFUpload, when the only alternative may be to use insecure code.
This is a fork of SWFUpload 188.8.131.52 and includes cross-site scripting fixes that have been reported by Szymon Gruszecki (CVE-2013-2205 and CVE-2012-2399), and Neal Poole and Nathan Partlan (CVE-2012-3414). It also includes fixes from Yelp’s engineering team for CVE-2012-2399.
WordPress 3.5.2, released moments ago, includes fixes for CVE-2013-2205 and CVE-2012-2399. WordPress 3.3.2 (2012-04-20) included a fix for CVE-2012-3414 and an incomplete fix for CVE-2012-2399.
If you think you have found a vulnerability in this fork of SWFUpload, we appreciate your help in disclosing it to us responsibly. Please email reports of security vulnerabilities to swfupload-security AT wordpress.org. These reports will be reviewed by the WordPress security team and by security researchers contributing to this project, including Neal and Szymon.