Vulnerability 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.
CVSS Score
CRITICAL
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| X.Org | Libx11 | < 1.7.1 |
| X.Org | X Window System | <= x11r7.7 |
| Fedoraproject | Fedora | 33 |
Related Weaknesses (CWE)
References
- http://packetstormsecurity.com/files/162737/libX11-Insufficient-Length-Check-InjExploitThird Party AdvisoryVDB Entry
- http://seclists.org/fulldisclosure/2021/May/52Mailing ListThird Party Advisory
- http://www.openwall.com/lists/oss-security/2021/05/18/2Mailing ListThird Party Advisory
- https://gitlab.freedesktop.org/xorg/lib/libx11/-/commit/8d2e02ae650f00c4a53deb62Third Party Advisory
- https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b
- https://lists.apache.org/thread.html/r61db8e7dcb56dc000a5387a88f7a473bacec5ee01b
- https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c2
- https://lists.apache.org/thread.html/rbf4ce74b0d1fa9810dec50ba3ace0caeea677af7c2
- https://lists.debian.org/debian-lts-announce/2021/05/msg00021.htmlThird Party Advisory
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedorapro
- https://lists.freedesktop.org/archives/xorg/Third Party Advisory
- https://lists.x.org/archives/xorg-announce/2021-May/003088.htmlVendor Advisory
- https://security.gentoo.org/glsa/202105-16Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210813-0001/Third Party Advisory
- https://unparalleled.eu/blog/2021/20210518-using-xterm-to-navigate-the-huge-coloExploitThird Party Advisory
FAQ
What is CVE-2021-31535?
CVE-2021-31535 is a vulnerability with a CVSS score of 9.8 (CRITICAL). 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 ...
How severe is CVE-2021-31535?
CVE-2021-31535 has been rated CRITICAL with a CVSS base score of 9.8/10. This is considered a critical vulnerability requiring immediate attention.
Is there a patch for CVE-2021-31535?
Check the references section above for vendor advisories and patch information. Affected products include: X.Org Libx11, X.Org X Window System, Fedoraproject Fedora.