A libvncserver security update has been released for Debian GNU/Linux 9 LTS to address several minor vulnerabilities.

DLA 2347-1: libvncserver security update

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Debian LTS Advisory DLA-2347-1 debian-lts@lists.debian.org
  https://www.debian.org/lts/security/ Mike Gabriel
August 28, 2020   https://wiki.debian.org/LTS
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Package : libvncserver
Version : 0.9.11+dfsg-1.3~deb9u5
CVE ID : CVE-2019-20839 CVE-2020-14397 CVE-2020-14399 CVE-2020-14400
CVE-2020-14401 CVE-2020-14402 CVE-2020-14403 CVE-2020-14404
CVE-2020-14405

Several minor vulnerabilities have been discovered in libvncserver, a
server and client implementation of the VNC protocol.

CVE-2019-20839

libvncclient/sockets.c in LibVNCServer had a buffer overflow via a
long socket filename.

CVE-2020-14397

libvncserver/rfbregion.c has a NULL pointer dereference.

CVE-2020-14399

Byte-aligned data was accessed through uint32_t pointers in
libvncclient/rfbproto.c.

NOTE: This issue has been disputed by third parties; there is
reportedly "no trust boundary crossed".

CVE-2020-14400

Byte-aligned data was accessed through uint16_t pointers in
libvncserver/translate.c.

NOTE: This issue has been disputed by third parties. There is no
known path of exploitation or cross of a trust boundary.

CVE-2020-14401

libvncserver/scale.c had a pixel_value integer overflow.

CVE-2020-14402

libvncserver/corre.c allowed out-of-bounds access via encodings.

CVE-2020-14403

libvncserver/hextile.c allowed out-of-bounds access via encodings.

CVE-2020-14404

libvncserver/rre.c allowed out-of-bounds access via encodings.

CVE-2020-14405

libvncclient/rfbproto.c did not limit TextChat size.

For Debian 9 stretch, these problems have been fixed in version
0.9.11+dfsg-1.3~deb9u5.

We recommend that you upgrade your libvncserver packages.

For the detailed security status of libvncserver please refer to
its security tracker page at:
  https://security-tracker.debian.org/tracker/libvncserver

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