Mozilla has warned that the Vietnamese language pack of Firefox 2 was compromised as a result of a viral infection.

The language pack did not contain a virus itself, but code that resulted in users seeing unwanted ads. More malicious action might have been possible as a result of the security flaw, the probable result of a developer's machine getting infected rather than a deliberate backdoor.

Mozilla said it does virus scans at upload time, but the virus scanner did not catch this issue until several months after the upload. It said it would revamp its testing procedure following the incident, the first of its kind to affect browser software.

A new Vietnamese language pack will be available shortly. In the meantime, Vietnamese language pack users are advised to disable this package using the add-ons dialogue on the Tools menu.

Mozilla's statement can be found here and there's more on Bugzilla here. ®

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