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Improper Link Resolution Before File Access ('Link Following')

CVE-2026-22702

Medium
4.5/10

Summary

virtualenv is a tool for creating isolated virtual python environments. Prior to version 20.36.1, 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. This issue has been patched in version 20.36.1.

  • HIGH
  • LOCAL
  • LOW
  • UNCHANGED
  • NONE
  • LOW
  • LOW
  • LOW

CWE-59 - Improper Link Resolution Before File Access

'Improper link resolution before file access' occurs when software accesses a file resource but fails to verify that the file isn't a link or shortcut to another file. An attacker can potentially gain access to arbitrary files and from there the impact can vary, depending on the application, from sensitive data exposure to remote code execution.

References

Advisory Timeline

  • Published