Bowser builder Mozilla has admitted that two Firefox add-ons which were flagged as containing malware last week are, in fact, completely harmless.
In a blog posting, a red-faced Mozilla spokescheese said: "Last week, we disclosed two instances of suspected malware in experimental add-ons on AMO. Since that disclosure, we’ve worked with security experts and add-on developers to determine that the suspected trojan in Version 4.0 of Sothink Video Downloader was a false positive and the extension does not include malware.
"The same investigation also confirmed that the Master Filer extension included a valid instance of a trojan. Our estimate of 6,000 affected downloads has been revised to under 700. The Sothink Video Downloader has been re-enabled on AMO.
"We apologize to our users and the developers of Sothink for any inconvenience this has caused."
Insecurity experts from McAfee gave the add-ons the all clear.