CVE-2017-2624
xorg-x11-server: timing attack against MIT Cookie
Severity
LowRed Hat Product Security
CVSS 3.0
Review impact separately from score.
Published · February 28, 2017
Updated · June 30, 2026
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.
Statement
Red Hat Product Security has rated this issue as having Low security impact. This issue is not currently planned to be addressed in future updates. For additional information, refer to the Issue Severity Classification: https://access.redhat.com/security/updates/classification/.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.0 · 5.9CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N
CWE-385 · Covert Timing Channel