CVE-2021-31800: Path traversal in impacket

The vulnerability stems from insufficient path validation in file operation functions. The advisory explicitly references line numbers in smbserver.py related to these functions. The fix commit (49c643b) introduced path prefix checks, confirming that these functions previously lacked traversal protection. Functions like openFile used os.path.join with user-controlled filenames, while findFirst2 processed search patterns without sanitization. The high confidence comes from direct code references in advisories and the nature of the vulnerability (CWE-22).