hello irvanoz, these crashes appear to be happening when the system is low on available memory. from the crash report itself it's not clear what causes the high RAM usage though.

one thing that is troubling in the crash report though is the presence of two files that hook into firefox ({f9d2f209-1697-4837-85f2-d88e4c9f7c81}.dll & wisenwizardBAApp.dll), which are probably malicious. please try to run a full scan of the system with multiple security tools recommended at Troubleshoot Firefox issues caused by malware.

You can also try to disable hardware acceleration in Firefox.

• Tools > Options > Advanced > General > Browsing: "Use hardware acceleration when available"

You need to close and restart Firefox after toggling this setting.

• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes
• https://support.mozilla.org/kb/upgrade-graphics-drivers-use-hardware-acceleration