CVE-2021-31535

NameCVE-2021-31535
DescriptionLookupCol.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.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)
ReferencesDLA-2666-1, DSA-4920-1
NVD severityhigh
Debian Bugs988737

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
libx11 (PTS)stretch2:1.6.4-3+deb9u1vulnerable
stretch (security)2:1.6.4-3+deb9u4fixed
buster, buster (security)2:1.6.7-1+deb10u2fixed
bullseye, sid2:1.7.1-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
libx11sourcestretch2:1.6.4-3+deb9u4DLA-2666-1
libx11sourcebuster2:1.6.7-1+deb10u2DSA-4920-1
libx11source(unstable)2:1.7.1-1988737

Notes

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

Search for package or bug name: Reporting problems