E-filing taxes? Watch out for fraud.

If you’re planning on filing your taxes online, caution is advised.

An audit released this week by Internet security nonprofit the Online Trust Alliance found that 46 percent, or 6 out of 13 tax software websites in an IRS program, failed cybersecurity protocols. The websites are part of IRS Free File program, which lets anyone who made under $62,000 in 2015 file taxes electronically for free. Seventy percent of American taxpayers can participate in the program, which has been around since 2003.

Some of the websites had issues with lack of email authentication, according to the OTA, which lets cyber criminals send out phishing emails, fake emails purporting to be from a company. Other sites had vulnerabilities that could lead to personal information being stolen. The report was sponsored by cybersecurity companies Agari, DigiCert and Symantec.