FREAK, the vulnerability is actually quite old already. “To comply with 1990s-era U.S. export restrictions on cryptography, SSL 3.0 and TLS 1.0 supported reduced-strength DHE_EXPORT ciphersuites that were restricted to primes no longer than 512 bits”, the released paper reads.
Luckily the team has already been in touch with most of the browser developers which means that there are either already fixes available (namely for the Internet Explorer) or will be very very soon.
Make sure you have the most recent version of your web browser installed: Google Chrome (including Android Browser), Mozilla Firefox, Microsoft Internet Explorer, and Apple Safari are all deploying fixes for the Logjam attack. If you run a web or mail server you should disable support for export cipher suites and generate a unique 2048-bit Diffie-Hellman group.
More information on LogJam can be found on the dedicated page.