CVE-2013-7439: Canonical Ubuntu Linux

High severity, CVSS 7.5. EPSS: 4.3% chance of exploitation in the next 30 days.

Multiple off-by-one errors in the (1) MakeBigReq and (2) SetReqLen macros in include/X11/Xlibint.h in X11R6.x and libX11 before 1.6.0 allow remote attackers to have unspecified impact via a crafted request, which triggers a buffer overflow.

Affected products

• Canonical Ubuntu Linux: version 12.04 only; version 14.04 only; version 14.10 only
• Debian Debian Linux: version 7.0 only
• X.org LIBX11: version 1.0.1 only; version 1.0.2 only; version 1.0.3 only; version 1.1 only; version 1.1.4 only; version 1.1.5 only; …
• X.org x11: version 6.0 only; version 6.1 only; version 6.3 only; version 6.4 only; version 6.5.1 only; version 6.6 only; …

Published 2015-04-16. Last modified 2026-06-17.