If the value passed to os.path.expandvars() is user-controlled a performance degradation is possible when expanding environment variables.
7.1.1+dfsg-17.2.0+dfsg-17.3.0+dfsg-17.3.0+dfsg-1ubuntu27.3.0+dfsg-1ubuntu37.3.1+dfsg-47.3.1+dfsg-4ubuntu0.13.10.12-1~22.04.123.12.3-1ubuntu0.97.3.19+dfsg-17.3.19+dfsg-27.3.20+dfsg-17.3.20+dfsg-33.13.7-1ubuntu0.13.14.0-13.14.0-1ubuntu0.13.14.0-1ubuntu0.23.14.0-1ubuntu0.33.14.0~a7-0ubuntu13.14.0~b1-13.14.0~b3-13.14.0~rc1-13.14.0~rc2-13.14.0~rc3-13.4.3-1ubuntu1~14.04.7+esm173.5.2-2ubuntu0~16.04.4~14.04.1+esm82.7.12-1ubuntu0~16.04.18+esm213.5.2-2ubuntu0~16.04.13+esm20Exploitability
AV:LAC:LAT:PPR:HUI:NVulnerable System
VC:NVI:NVA:LSubsequent System
SC:NSI:NSA:NCVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N