CVE-2017-18922

It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A malicious attacker could exploit this by sending specially crafted WebSocket frames to a server, causing a heap-based buffer overflow.

Published: 2020-06-30 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-18922 is rated Moderate Risk (62.8/100): CVSS Critical severity, with medium exploitation likelihood (EPSS 2.26%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-18922

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 6.87% 2.26% -4.61%
2 2026-04-22 4.78% 6.87% +2.09%
3 2025-12-28 — 4.78% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-18922

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
9.8 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 5.9 [email protected]
7.5 2.0 HIGH
AV:N/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 6.4 [email protected]

Weakness enumeration for CVE-2017-18922

OS Trackers for CVE-2017-18922

vendor priority summary link
debian not yet assigned CVE-2017-18922 not yet assigned priority: Debian including 1 source packages (libvncserver), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-18922
redhat high — https://access.redhat.com/security/cve/CVE-2017-18922
suse high CVE-2017-18922 severity important: SUSE including 25 source package names (LibVNCServer, LibVNCServer-devel-0.9.10-4.22.1, …), 91 product×package rows across 51 product lines (HPE Helion OpenStack 8, SUSE Enterprise Storage 5, … (51 product lines)): Fixed 88, Known Not Affected 3. https://www.suse.com/security/cve/CVE-2017-18922/
ubuntu medium CVE-2017-18922 medium priority: Ubuntu including 3 source packages (libvncserver, veyon, x11vnc), 51 status rows across 17 suites (bionic, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 20, ignored 16, needs-triage 7, DNE 4, released 4. https://ubuntu.com/security/CVE-2017-18922

Affected software / configurations for CVE-2017-18922

Vendor Product Version Raw CPE
libvncserver_project libvncserver < 0.9.12 cpe:2.3:a:libvncserver_project:libvncserver:*:*:*:*:*:*:*:*
canonical ubuntu_linux 16.04 cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 18.04 cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
canonical ubuntu_linux 19.10 cpe:2.3:o:canonical:ubuntu_linux:19.10:*:*:*:*:*:*:*
canonical ubuntu_linux 20.04 cpe:2.3:o:canonical:ubuntu_linux:20.04:*:*:*:lts:*:*:*
opensuse leap 15.1 cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*
opensuse leap 15.2 cpe:2.3:o:opensuse:leap:15.2:*:*:*:*:*:*:*
fedoraproject fedora 31 cpe:2.3:o:fedoraproject:fedora:31:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
siemens simatic_itc1500_firmware >= 3.0.0.0, < 3.2.1.0 cpe:2.3:o:siemens:simatic_itc1500_firmware:*:*:*:*:*:*:*:*
siemens simatic_itc1500_pro_firmware >= 3.0.0.0, < 3.2.1.0 cpe:2.3:o:siemens:simatic_itc1500_pro_firmware:*:*:*:*:*:*:*:*
siemens simatic_itc1900_firmware >= 3.0.0.0, < 3.2.1.0 cpe:2.3:o:siemens:simatic_itc1900_firmware:*:*:*:*:*:*:*:*
siemens simatic_itc1900_pro_firmware >= 3.0.0.0, < 3.2.1.0 cpe:2.3:o:siemens:simatic_itc1900_pro_firmware:*:*:*:*:*:*:*:*
siemens simatic_itc2200_firmware >= 3.0.0.0, < 3.2.1.0 cpe:2.3:o:siemens:simatic_itc2200_firmware:*:*:*:*:*:*:*:*
siemens simatic_itc2200_pro_firmware >= 3.0.0.0, < 3.2.1.0 cpe:2.3:o:siemens:simatic_itc2200_pro_firmware:*:*:*:*:*:*:*:*

References for CVE-2017-18922

URL Tags
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00020.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00028.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.html Mailing List Third Party Advisory
http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.html Mailing List Third Party Advisory
http://www.openwall.com/lists/oss-security/2020/06/30/3 Mailing List Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1852356 Issue Tracking Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf Patch Third Party Advisory
https://github.com/LibVNC/libvncserver/commit/aac95a9dcf4bbba87b76c72706c3221a842ca433 Patch Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY/
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NVP7TJVYJDXDFRHVQ3ENEN3H354QPXEZ/
https://usn.ubuntu.com/4407-1/ Patch Third Party Advisory
https://www.openwall.com/lists/oss-security/2020/06/30/2 Mailing List Third Party Advisory
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