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CVE-2021-31535

Publication date 18 May 2021

Last updated 24 July 2024

Ubuntu priority

Medium

Why this priority?

Cvss 3 Severity Score

9.8 · Critical

Score breakdown

LookupCol.c in X.Org X through X11R7.7 and libX11 before 1.7.1 might allow remote attackers to execute arbitrary code. The libX11 XLookupColor request (intended for server-side color lookup) contains a flaw allowing a client to send color-name requests with a name longer than the maximum size allowed by the protocol (and also longer than the maximum packet size for normal-sized packets). The user-controlled data exceeding the maximum size is then interpreted by the server as additional X protocol requests and executed, e.g., to disable X server authorization completely. For example, if the victim encounters malicious terminal control sequences for color codes, then the attacker may be able to take full control of the running graphical session.

Status

Package Ubuntu Release Status
libx11 22.04 LTS jammy
Fixed 1.7.0-2ubuntu1
21.10 impish
Fixed 1.7.0-2ubuntu1
21.04 hirsute
Fixed 2:1.7.0-2ubuntu0.1
20.10 groovy
Fixed 2:1.6.12-1ubuntu0.1
20.04 LTS focal
Fixed 2:1.6.9-2ubuntu1.2
18.04 LTS bionic
Fixed 2:1.6.4-3ubuntu0.4
16.04 LTS xenial
14.04 LTS trusty

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Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package Patch details
libx11

Severity score breakdown

Parameter Value
Base score 9.8 · Critical
Attack vector Network
Attack complexity Low
Privileges required None
User interaction None
Scope Unchanged
Confidentiality High
Integrity impact High
Availability impact High
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H