CVE-2021-31535

critical

Description

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.

References

https://unparalleled.eu/blog/2021/20210518-using-xterm-to-navigate-the-huge-color-space/

https://unparalleled.eu/publications/2021/advisory-unpar-2021-1.txt

https://lists.freedesktop.org/archives/xorg/

https://www.openwall.com/lists/oss-security/2021/05/18/2

https://www.openwall.com/lists/oss-security/2021/05/18/3

https://lists.x.org/archives/xorg-announce/2021-May/003088.html

https://lists.debian.org/debian-lts-announce/2021/05/msg00021.html

http://packetstormsecurity.com/files/162737/libX11-Insufficient-Length-Check-Injection.html

https://www.debian.org/security/2021/dsa-4920

http://www.openwall.com/lists/oss-security/2021/05/18/2

https://security.gentoo.org/glsa/202105-16

http://seclists.org/fulldisclosure/2021/May/52

https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/8d2e02ae650f00c4a53deb625211a0527126c605

https://security.netapp.com/advisory/ntap-20210813-0001/

https://lists.fedoraproject.org/archives/list/[email protected]/message/TEOT4RLB76RVPJQKGGTIKTBIOLHX2NR6/

https://lists.apache.org/thread.html/[email protected]%3Cusers.kafka.apache.org%3E

https://lists.apache.org/thread.html/[email protected]%3Cdev.kafka.apache.org%3E

https://lists.apache.org/thread.html/[email protected]%3Cusers.kafka.apache.org%3E

https://lists.apache.org/thread.html/[email protected]%3Cdev.kafka.apache.org%3E

Details

Source: MITRE

Published: 2021-05-27

Updated: 2021-09-23

Type: CWE-120

Risk Information

CVSS v2

Base Score: 7.5

Vector: AV:N/AC:L/Au:N/C:P/I:P/A:P

Impact Score: 6.4

Exploitability Score: 10

Severity: HIGH

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Impact Score: 5.9

Exploitability Score: 3.9

Severity: CRITICAL