Description
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.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libx11 | 2:1.6.0-1 | — |
| Debian 13 | libx11 | 2:1.6.0-1 | — |
| Debian 12 | libx11 | 2:1.6.0-1 | — |
| Debian 7 | libx11 | 2:1.5.0-1+deb7u2 | DSA-3224-1 |
| Debian 6.0 | libx11 | 2:1.3.3-4+squeeze2 | DLA-199-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | libxrender | 1:0.9.8-1build0.14.04.1 | USN-2568-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | libX11 +2 | 1.6.0-2.2.el6 | RHSA-2014:1436 |
| RHEL 6 | libXcursor +1 | 1.1.14-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXext +1 | 1.3.2-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXfixes +1 | 5.0.1-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXi +1 | 1.7.2-2.2.el6 | RHSA-2014:1436 |
| RHEL 6 | libXp +1 | 1.0.2-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXrandr +1 | 1.4.1-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXrender +1 | 0.9.8-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXres +1 | 1.0.7-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXt +1 | 1.1.4-6.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXtst +1 | 1.2.2-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXv +1 | 1.0.9-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXvMC +1 | 1.0.8-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXxf86dga +1 | 1.1.4-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libXxf86vm +3 | 1.1.3-2.1.el6 | RHSA-2014:1436 |
| RHEL 6 | libdmx +1 | 1.1.3-3.el6 | RHSA-2014:1436 |
| RHEL 6 | libxcb +3 | 1.9.1-2.el6 | RHSA-2014:1436 |
| RHEL 6 | xcb-proto | 1.8-3.el6 | RHSA-2014:1436 |
| RHEL 6 | xkeyboard-config +1 | 2.11-1.el6 | RHSA-2014:1436 |
| RHEL 6 | xorg-x11-proto-devel | 7.7-9.el6 | RHSA-2014:1436 |
| RHEL 6 | xorg-x11-xtrans-devel | 1.3.4-1.el6 | RHSA-2014:1436 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 11 SP4 | xorg-x11-libX11 | 7.4-5.11.15.1 | SUSE-SU-2015:1334-1 |
| SLES 11 SP3 | xorg-x11-libX11 | 7.4-5.11.15.1 | SUSE-SU-2015:1334-1 |
| SLES 11 SP2 | xorg-x11-libX11 | 7.4-5.11.15.1 | SUSE-SU-2015:1334-1 |
| SLES 11 SP1 | xorg-x11-libX11 | 7.4-5.11.15.1 | SUSE-SU-2015:1334-1 |
Show 2 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 11 SP4 | xorg-x11-libX11 | 7.4-5.11.15.1 | SUSE-SU-2015:1334-1 |
| SLES for SAP 11 SP3 | xorg-x11-libX11 | 7.4-5.11.15.1 | SUSE-SU-2015:1334-1 |
Advisories 5
- RHSA-2014:1436 Red Hat Security Advisory: X11 client libraries security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- USN-2568-1 libx11, libxrender vulnerability Ubuntu Security Notices (USN) · Apr 22, 2026
- DLA-199-1 libx11 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-3224-1 libx11 - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2015:1334-1 Security update for xorg-x11-libX11 SUSE / openSUSE Security Updates · Feb 4, 2026
References
- USN-2568-1 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/bulletinjul2015-2511963.html
- 73962 vdb-entry
- DSA-3224 vendor-advisory
- [oss-security] 20150409 Re: CVE Request: libX11: buffer overflow in MakeBigReq macro mailing-list
- [xorg-announce] 20150414 [ANNOUNCE] X.Org Security Advisory: Buffer overflow in MakeBigReq macro mailing-list
- https://bugs.freedesktop.org/show_bug.cgi?id=56508