Google on Wednesday updated its May 2021 Android Security Bulletin to disclose that four of the security vulnerabilities that were patched earlier this month by Arm and Qualcomm may have been exploited in the wild as zero-days.

"There are indications that CVE-2021-1905, CVE-2021-1906, CVE-2021-28663 and CVE-2021-28664 may be under limited, targeted exploitation," the search giant said in an updated alert.

The four flaws impact Qualcomm Graphics and Arm Mali GPU Driver modules —

• CVE-2021-1905 (CVSS score: 8.4) - A use-after-free flaw in Qualcomm's graphics component due to improper handling of memory mapping of multiple processes simultaneously.
• CVE-2021-1906 (CVSS score: 6.2) - A flaw concerning inadequate handling of address deregistration that could lead to new GPU address allocation failure.
• CVE-2021-28663 (CVSS score: NA) - A vulnerability in Arm Mali GPU kernel that could permit a non-privileged user to make improper operations on GPU memory, leading to a use-after-free scenario that could be exploited to gain root privilege or disclose information.
• CVE-2021-28664 (CVSS score: NA) - An unprivileged user can achieve read/write access to read-only memory, enabling privilege escalation or a denial-of-service (DoS) condition due to memory corruption.

Successful exploitation of the weaknesses could grant an adversary carte blanche access to the targeted device and take over control. It's, however, not clear how the attacks themselves were carried out, the victims that may have been targeted, or the threat actors that may be abusing them.

The development marks one of the rare instances where zero-day bugs in Android have been spotted in real-world cyber offensives.

Earlier this March, Google revealed that a vulnerability affecting Android devices that use Qualcomm chipsets (CVE-2020-11261) was being weaponized by adversaries to launch targeted attacks. The other flaw is CVE-2019-2215, a vulnerability in Binder — Android's inter-process communication mechanism — that's said to have been allegedly exploited by the NSO Group as well as SideWinder threat actor to compromise a victim's device and collect user information.