I too got this very unexpected, presumably false positive from an old Firefox library file:
Malwarebytes
www.malwarebytes.com
-Log Details-
Scan Date: 3/11/23
Scan Time: 2:02 AM
Log File: 9e7edf88-bfda-11ed-ab41-70bc1064cc83.json
-Software Information-
Version: 4.5.23.241
Components Version: 1.0.1927
Update Package Version: 1.0.66563
License: Premium
-System Information-
OS: Windows 10 (Build 19045.2604)
CPU: x64
File System: NTFS
User: System
-Scan Summary-
Scan Type: Threat Scan
Scan Initiated By: Scheduler
Result: Completed
Objects Scanned: 361886
Threats Detected: 1
Threats Quarantined: 0
Time Elapsed: 15 min, 5 sec
-Scan Options-
Memory: Enabled
Startup: Enabled
Filesystem: Enabled
Archives: Enabled
Rootkits: Enabled
Heuristics: Enabled
PUP: Detect
PUM: Detect
-Scan Details-
Process: 0
(No malicious items detected)
Module: 0
(No malicious items detected)
Registry Key: 0
(No malicious items detected)
Registry Value: 0
(No malicious items detected)
Registry Data: 0
(No malicious items detected)
Data Stream: 0
(No malicious items detected)
Folder: 0
(No malicious items detected)
File: 1
Malware.AI.4081612927, [path to browser]MOZAVUTIL.DLL, No Action By User, 1000000, -213354369, 1.0.66563, 088F5E45E7BAF681F348787F, dds, 02203522, 330637F8F5F41A4D55790C58BCEB0DCD, 8434C64510FAA9D6EAAA586A6F0C49367679ADEF5CCF14AD6F93CD76746486BE
Physical Sector: 0
(No malicious items detected)
WMI: 0
(No malicious items detected)
(end)