Anyone who has used sIFR on past websites should consider this article released by sIFR developer Mark Wubben earlier this month:

“Malicious websites can trick visitors into running JavaScript code on domains hosting sIFR movies. No exploits are known…” [more on the security flaw]

sIFR 3 users are advised to update to revision 278*
siFR 2 users are advised to update to sIFR 2.0.3*

*Make sure to update the sifr.js file and re-export all movies.