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

CVE-2021-35939

Medium
6.7/10

Summary

It was found that the fix for CVE-2017-7500 and CVE-2017-7501 was incomplete: the check was only implemented for the parent directory of the file to be created. A local unprivileged user who owns another ancestor directory could potentially use this flaw to gain root privileges. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

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

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