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Vulnerability record · CVE-2016-9942 · published 31 December 2016

CVE-2016-9942: Libvncserver project libvncserver memory buffer overflow vulnerability

LLibvncserver Project · Libvncserver

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.

9.8 CVSS 3.0 Critical EPSS 3.7% · top 10.5% CWE-119 · Memory buffer overflow
9.8CVSS 3.0 base score, v2 7.5
3.7%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
14References
17 Jun 2026Last modified by NVD

Description

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.

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
http://www.debian.org/security/2017/dsa-3753
http://www.securityfocus.com/bid/95170
https://github.com/LibVNC/libvncserver/pull/137
https://github.com/LibVNC/libvncserver/releases/tag/LibVNCServer-0.9.11
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://security.gentoo.org/glsa/201702-24
https://usn.ubuntu.com/4587-1/
http://www.debian.org/security/2017/dsa-3753
http://www.securityfocus.com/bid/95170
https://github.com/LibVNC/libvncserver/pull/137
https://github.com/LibVNC/libvncserver/releases/tag/LibVNCServer-0.9.11
https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
https://security.gentoo.org/glsa/201702-24
https://usn.ubuntu.com/4587-1/

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Source: NIST National Vulnerability Database (record CVE-2016-9942), CISA KEV, FIRST EPSS (scores of 2026-09-28). This page is refreshed as NVD updates the record.