Debian Long Term Support / LTS Security Information / 2017 / Security Information -- DLA-1008-1 libxml2

Debian Security Advisory

DLA-1008-1 libxml2 -- LTS security update

Date Reported:

30 Jun 2017

Affected Packages:

libxml2

Vulnerable:

Yes

Security database references:

In Mitre's CVE dictionary: CVE-2017-7375, CVE-2017-9047, CVE-2017-9048, CVE-2017-9049, CVE-2017-9050.

More information:

• CVE-2017-7375

  Missing validation for external entities in xmlParsePEReference

• CVE-2017-9047 / CVE-2017-9048

  A buffer overflow was discovered in libxml2 20904-GITv2.9.4-16-g0741801. The function xmlSnprintfElementContent in valid.c is supposed to recursively dump the element content definition into a char buffer buf of size size. The variable len is assigned strlen(buf). If the content->type is XML_ELEMENT_CONTENT_ELEMENT, then (i) the content->prefix is appended to buf (if it actually fits) whereupon (ii) content->name is written to the buffer. However, the check for whether the content->name actually fits also uses len rather than the updated buffer length strlen(buf). This allows us to write about size many bytes beyond the allocated memory. This vulnerability causes programs that use libxml2, such as PHP, to crash.

• CVE-2017-9049 / CVE-2017-9050

  libxml2 20904-GITv2.9.4-16-g0741801 is vulnerable to a heap-based buffer over-read in the xmlDictComputeFastKey function in dict.c. This vulnerability causes programs that use libxml2, such as PHP, to crash. This vulnerability exists because of an incomplete fix for libxml2 Bug 759398.

For Debian 7 Wheezy, these problems have been fixed in version 2.8.0+dfsg1-7+wheezy8.

We recommend that you upgrade your libxml2 packages.

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS