CVE-2021-31535
CRITICALEPSS 95th pctlDescription
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.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Exploit Intelligence
Very high risk: more likely to be exploited than 95% of all known CVEs.
References
- http://packetstormsecurity.com/files/162737/libX11-Insufficient-Length-Check-Injection.html
- http://seclists.org/fulldisclosure/2021/May/52
- http://www.openwall.com/lists/oss-security/2021/05/18/2
- https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/8d2e02ae650f00c4a53deb625211a0527126c605
- https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cdev.kafka.apache.org%3E
- https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b9ff3f55308aacc%40%3Cusers.kafka.apache.org%3E
- https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cdev.kafka.apache.org%3E
- https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c27a97111c06ccb7%40%3Cusers.kafka.apache.org%3E
- https://lists.debian.org/debian-lts-announce/2021/05/msg00021.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/TEOT4RLB76RVPJQKGGTIKTBIOLHX2NR6/
- https://lists.freedesktop.org/archives/xorg/
- https://lists.x.org/archives/xorg-announce/2021-May/003088.html
- https://security.gentoo.org/glsa/202105-16
- https://security.netapp.com/advisory/ntap-20210813-0001/
- 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://www.debian.org/security/2021/dsa-4920
- https://www.openwall.com/lists/oss-security/2021/05/18/2
- https://www.openwall.com/lists/oss-security/2021/05/18/3
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Start freeThis product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.