Adobe is set to release an emergency update on Friday to its Flash Player for Windows, Mac, Linux and Solaris, shoring up a zero-day vulnerability disclosed earlier this week. Users of Flash for Google Chrome will receive the update on Thursday via the browser's auto-update mechanism. Attackers are actively exploiting the flaw under the guise of a legitimate Microsoft Word document, Adobe has warned. The company expects to provide an update no later than the week of April 25 for Adobe Acrobat X and earlier for Windows and Mac, Adobe Reader X for Mac and Adobe Reader 9.4.3 and earlier for Windows and Mac. Adobe Reader X for Windows is expected to be updated with the next quarterly release, scheduled for June 14.