CVE-2017-2624

Severity CVSS v4.0:

Pending analysis

Type:

Unavailable / Other

Publication date:

27/07/2018

Last modified:

29/08/2025

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.

Impact

Vector 3.x

CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N CVSS v3.1 Severity and Metrics:

Base Score: 5.90 MEDIUM
Vector: CVSS:3.0/AV:L/AC:H/PR:N/UI:N/S:C/C:H/I:N/A:N

Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Changed
Confidentiality (C): High
Integrity (I): None
Availability (A): None

Base Score 3.x

5.90

Severity 3.x

MEDIUM

Vector 2.0

AV:L/AC:M/Au:N/C:P/I:N/A:N CVSS v2.0 Severity and Metrics:

Base Score: 1.90 LOW
Vector: AV:L/AC:M/Au:N/C:P/I:N/A:N

Attack Vector (AV): Local
Attack Complexity (AC): Medium
Authentication (Au): None
Confidentiality (C): Physical
Integrity (I): None
Availability (A): None