RHSA-2012:0016 - Security Advisory

Topic

Updated libxml2 packages that fix several security issues are now available
for Red Hat Enterprise Linux 4.

The Red Hat Security Response Team has rated this update as having
important security impact. Common Vulnerability Scoring System (CVSS) base
scores, which give detailed severity ratings, are available for each
vulnerability from the CVE links in the References section.

Description

The libxml2 library is a development toolbox providing the implementation
of various XML standards. One of those standards is the XML Path Language
(XPath), which is a language for addressing parts of an XML document.

A heap-based buffer overflow flaw was found in the way libxml2 decoded
entity references with long names. A remote attacker could provide a
specially-crafted XML file that, when opened in an application linked
against libxml2, would cause the application to crash or, potentially,
execute arbitrary code with the privileges of the user running the
application. (CVE-2011-3919)

An off-by-one error, leading to a heap-based buffer overflow, was found in
the way libxml2 parsed certain XML files. A remote attacker could provide a
specially-crafted XML file that, when opened in an application linked
against libxml2, would cause the application to crash or, potentially,
execute arbitrary code with the privileges of the user running the
application. (CVE-2011-0216)

A flaw was found in the way libxml2 parsed certain XPath expressions. If an
attacker were able to supply a specially-crafted XML file to an application
using libxml2, as well as an XPath expression for that application to run
against the crafted file, it could cause the application to crash.
(CVE-2011-2834)

Note: Red Hat does not ship any applications that use libxml2 in a way that
would allow the CVE-2011-2834 flaw to be exploited; however, third-party
applications may allow XPath expressions to be passed which could trigger
this flaw.

An out-of-bounds memory read flaw was found in libxml2. A remote attacker
could provide a specially-crafted XML file that, when opened in an
application linked against libxml2, would cause the application to crash.
(CVE-2011-3905)

All users of libxml2 are advised to upgrade to these updated packages,
which contain backported patches to correct these issues. The desktop must
be restarted (log out, then log back in) for this update to take effect.

Solution

Before applying this update, make sure all previously-released errata
relevant to your system have been applied.

This update is available via the Red Hat Network. Details on how to
use the Red Hat Network to apply this update are available at
https://access.redhat.com/kb/docs/DOC-11259

Affected Products

• Red Hat Enterprise Linux Server 4 x86_64
• Red Hat Enterprise Linux Server 4 ia64
• Red Hat Enterprise Linux Server 4 i386
• Red Hat Enterprise Linux Workstation 4 x86_64
• Red Hat Enterprise Linux Workstation 4 ia64
• Red Hat Enterprise Linux Workstation 4 i386
• Red Hat Enterprise Linux Desktop 4 x86_64
• Red Hat Enterprise Linux Desktop 4 i386
• Red Hat Enterprise Linux for IBM z Systems 4 s390x
• Red Hat Enterprise Linux for IBM z Systems 4 s390
• Red Hat Enterprise Linux for Power, big endian 4 ppc

Fixes

• BZ - 724906 - CVE-2011-0216 libxml2: Off-by-one error leading to heap-based buffer overflow in encoding
• BZ - 735751 - CVE-2011-2834 libxml2: double-free caused by malformed XPath expression in XSLT
• BZ - 767387 - CVE-2011-3905 libxml2 out of bounds read
• BZ - 771896 - CVE-2011-3919 libxml2: Heap-based buffer overflow when decoding an entity reference with a long name

CVEs

• CVE-2011-0216
• CVE-2011-2834
• CVE-2011-3919
• CVE-2011-3905

References

• https://access.redhat.com/security/updates/classification/#important