CVE-2021-31535
Publication date 18 May 2021
Last updated 24 July 2024
Ubuntu priority
Cvss 3 Severity Score
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
|
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 |
Fixed 2:1.6.3-1ubuntu2.2+esm1
|
|
14.04 LTS trusty |
Fixed 2:1.6.2-1ubuntu2.1+esm2
|
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Get Ubuntu ProSeverity 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 |
References
Related Ubuntu Security Notices (USN)
- USN-4966-1
- libx11 vulnerability
- 25 May 2021
- USN-4966-2
- libx11 vulnerability
- 25 May 2021
Other references
- https://www.openwall.com/lists/oss-security/2021/05/18/2
- https://www.openwall.com/lists/oss-security/2021/05/18/3
- https://unparalleled.eu/publications/2021/advisory-unpar-2021-1.txt
- https://unparalleled.eu/blog/2021/20210518-using-xterm-to-navigate-the-huge-color-space/
- https://www.cve.org/CVERecord?id=CVE-2021-31535