Missing earlier versions work around for "XSS Vulnerability in strip_tags"

The rubyonrails-security announcement for CVE-2012-3465 "XSS
Vulnerability in strip_tags" mentions that a work around for earlier
versions should be attached, but there's none, only patches for 3.0
series and up.

Is the work around available? If so, where can I get hold of it?

Thanks in advance,
Peter