VULNERABILITY INTELLIGENCE

CVE-2017-2624

CVSS score5.9 MEDIUM
EPSS probability0.67%
CISA KEVNot currently listed
Published2018-07-27
Last modified2026-06-17
CVSS vectorCVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Description

It was found that xorg-x11-server before 1.19.0 including uses memcmp() to check the received MIT cookie against a series of valid cookies. If the cookie is correct, it is allowed to attach to the Xorg session. Since most memcmp() implementations return after an invalid byte is seen, this causes a time difference between a valid and invalid byte, which could allow an efficient brute force attack.

Weakness classification

  • CWE-200: Exposure of Sensitive Information to an Unauthorized Actor
  • CWE-385: Covert Timing Channel

Primary references