BatchActivator.quote() returned its input unchanged, the only activator with no escaping at all. –prompt, the VIRTUALENV_PROMPT environment variable, and the config file all set the prompt, and activate.bat writes it straight into @set "VAR=value". A prompt containing a double quote closes that string early, and whatever follows runs as live cmd.exe syntax: $ virtualenv –prompt 'x" & calc & "' venv $ venv\Scripts\activate.bat runs calc the moment someone activates the …
The generated activate (bash/zsh) and activate.fish scripts interpolate a shlex.quote-ed value into a position that quotes it a second time. The extra quotes terminate the quoted run early and leave part of the value parsed as shell code, so a path containing shell metacharacters runs commands when a user sources the activation script. activate is affected through the virtual environment's own path, on the branch that reports a relocated environment: …
download_wheel() runs pip download and hands the result straight to the seeder, with nothing checking the bytes it gets back. The embedded pip and setuptools wheels carry a BUNDLE_SHA256 that virtualenv checks on every load, but a wheel fetched over the network for the periodic-update feature or the –download flag had no equivalent verification. A compromised index, a stale mirror, or a MITM'd download (when TLS is intercepted, e.g. via …
pyvenv.cfg is a line-based format with no escape syntax. PyEnvCfg.write() wrote values verbatim, while PyEnvCfg._read_values() parses the file with str.splitlines(). A value containing a line boundary therefore became additional configuration lines, and because reading is last-wins, the injected keys replaced any key written earlier in the file.
TOCTOU (Time-of-Check-Time-of-Use) vulnerabilities in virtualenv allow local attackers to perform symlink-based attacks on directory creation operations. An attacker with local access can exploit a race condition between directory existence checks and creation to redirect virtualenv's app_data and lock file operations to attacker-controlled locations. Affected versions: All versions up to and including 20.36.1 Affected users: Any user running virtualenv on multi-user systems where untrusted local users have filesystem access to shared …