(credit: Wikimedia)

Developers of the widely used LastPass password manager are scrambling to fix a serious vulnerability that makes it possible for malicious websites to steal user passcodes and in some cases execute malicious code on computers running the program.

The flaw, which affects the latest version of the LastPass browser extension, was briefly described on Saturday by Tavis Ormandy, a researcher with Google’s Project Zero vulnerability reporting team. When people have the LastPass binary running, the vulnerability allows malicious websites to execute code of their choice. Even when the binary isn’t present, the flaw can be exploited in a way that lets malicious sites steal passwords from the protected LastPass vault. Ormandy said he developed a proof-of-concept exploit and sent it to LastPass officials. Developers now have three months to patch the hole before Project Zero discloses technical details.

“It will take a long time to fix this properly,” Ormandy said. “It’s a major architectural problem. They have 90 days, no need to scramble!”