Pinterest users are warned that a dangerous Acai berry diet scam is targeting the site, flooding posts with links to a dodgy weightloss website.
The posts, which claim that the diet product is sponsored by Pinterest, are added under random images in comments and are followed by a link to an external website.
Internet security firm Sophos warns pinners to be cautious and avoid clicking links to this particular scam.
They say that Pinterest is at particular risk of attacks like this, with its open commenting system and the sharing-oriented nature of the site.
Graham Cluley, senior technology consultant at Sophos, said: "Unless Pinterest gets serious about preventing spammers from abusing its systems, the problem is just going to get bigger and bigger. We've seen similar Acai Berry websites promoted multiple times in the past by spammers, who earn commission from driving traffic in the direction of the fruity dieticians, and this is not likely to be the last."
Dieting tips are often used by scammers, according to the security specialists, and with a female-focus, could become a real risk for Pinterest.
"If Pinterest continues to grow, more spammers will be tempted to exploit the website's userbase. Users of Pinterest would be wise to take care over their accounts, and think carefully about what they 'repin' and what links they click on. As with any social media website, users need to have a critical eye and not be fooled by simple spam traps," Cluley said.