Microsoft and Adobe have independently patched security for a range of their products, including Internet Explorer and Flash Player.
Both releases fix bugs that left users exposed to remote code execution, in which a hacker can hijack a victim's machine, and were announced on Patch Tuesday, Microsoft's regular update slot.
Microsoft said: "An attacker who successfully exploited these [Internet Explorer] vulnerabilities could gain the same user rights as the current user.
"Customers whose accounts are configured to have fewer user rights on the system could be less impacted than those who operate with administrative user rights."
Only one of the vulnerabilities fixed on Microsoft's web browser was publicly disclosed, with 25 other bugs privately reported to the company.
As well as its Flash Player, Adobe patched its Integrated Runtime (AIR) environment, which is used to run apps on Windows, Macintosh and some mobile operating systems.
Though some software will have updated automatically, users are advised to check their software manually to ensure it has been patched.