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Fencer Intel
critical 9.8

CVE-2016-9942 json

Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (app…

published 2016-12-31 9 y ago modified 2026-06-17 4 mo ago also EUVD-2016-10729

cvss
9.8
version 3.0, NVD
cisa kev
Not listed
not in CISA's catalog
epss
3.8%
EPSS 3.8% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted FramebufferUpdate message with the Ultra type tile, such that the LZO payload decompressed length exceeds what is specified by the tile dimensions.

Patch / fix

  • veyon Debian 13, Debian 12 4.1.4+repack1-1
  • libvncserver Debian 14, Debian 13, Debian 12 0.9.11+dfsg-1

debian advisories DEBIAN-CVE-2016-9942

  • italc Ubuntu 16.04 LTS 1:2.0.2+dfsg1-4ubuntu0.1
  • libvncserver Ubuntu 14.04 LTS 0.9.9+dfsg-1ubuntu1.2
  • libvncserver Ubuntu 16.04 LTS 0.9.10+dfsg-3ubuntu0.16.04.1

ubuntu advisories UBUNTU-CVE-2016-9942

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • LibVNCServer SLES for SAP 12 SP3, SLES for SAP 12 SP2, SLES for Raspberry Pi 12 SP2 +4 more 0.9.9-17.5.1
  • tigervnc SLES for SAP 12 SP2, SLES for Raspberry Pi 12 SP2, SLES 12 SP2 +1 more 1.6.0-16.4
  • tigervnc SLES for SAP 12 SP1, SLES 12 SP1, SLED 12 SP1 1.4.3-19.1
  • LibVNCServer SLES for SAP 11 SP4, SLES 11 SP4, SLE Software Development Kit 11 SP4 0.9.1-159.1

suse advisories SUSE-SU-2018:0830-1SUSE-SU-2017:0622-1SUSE-SU-2017:0519-1SUSE-SU-2017:0104-1

  • libvncserver Alpine 3.24, Alpine 3.23, Alpine 3.22 +16 more 0.9.11-r0
  • libvncserver Alpine 3.5, Alpine 3.4, Alpine 3.3 +1 more 0.9.10-r2

alpine advisories ALPINE-CVE-2016-9942

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • libvncserver Arch Linux 0.9.11-1

arch linux advisories AVG-124

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2016-9942 updated cvss 7.5

libvncserver: Heap-based buffer overflow in ultra.c

  • Red Hat Enterprise Linux 6 libvncserver Red Hat Enterprise Linux 7 libvncserver
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

3.82% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
NVD 3.0 9.8 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P

Classification

Weakness
  • CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.