Buffer Overflow Affecting libx11 package, versions <2:1.6.4-3ubuntu0.4


Severity

Recommended
medium

Based on Ubuntu security rating.

Threat Intelligence

EPSS
11.09% (96th percentile)

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  • Snyk IDSNYK-UBUNTU1804-LIBX11-1295521
  • published20 May 2021
  • disclosed27 May 2021

Introduced: 20 May 2021

CVE-2021-31535  (opens in a new tab)
CWE-120  (opens in a new tab)

How to fix?

Upgrade Ubuntu:18.04 libx11 to version 2:1.6.4-3ubuntu0.4 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libx11 package and not the libx11 package as distributed by Ubuntu. See How to fix? for Ubuntu:18.04 relevant fixed versions and status.

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

CVSS Scores

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