What’s Vulnerable › Vulnerabilities
CVE-2017-18922
- Severity: critical (CVSS 9.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 2.3% probability of exploitation in the next 30 days
- Public exploit or detection template: none known
- Published: 2020-06-30 · updated 2026-06-17
- Weakness: CWE-787
Description
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.
Affected products
- Canonical Ubuntu Linux: 16.04, 18.04, 19.10, 20.04
- Fedoraproject Fedora: 31, 32
- LibVNCServer: before 0.9.12 — fixed in 0.9.12
- openSUSE Leap: 15.1, 15.2
- Siemens Simatic Itc1500 Firmware: from 3.0.0.0 before 3.2.1.0 — fixed in 3.2.1.0
- Siemens Simatic Itc1500 Pro Firmware: from 3.0.0.0 before 3.2.1.0 — fixed in 3.2.1.0
- Siemens Simatic Itc1900 Firmware: from 3.0.0.0 before 3.2.1.0 — fixed in 3.2.1.0
- Siemens Simatic Itc1900 Pro Firmware: from 3.0.0.0 before 3.2.1.0 — fixed in 3.2.1.0
- Siemens Simatic Itc2200 Firmware: from 3.0.0.0 before 3.2.1.0 — fixed in 3.2.1.0
- Siemens Simatic Itc2200 Pro Firmware: from 3.0.0.0 before 3.2.1.0 — fixed in 3.2.1.0
How to fix
Upgrade to a fixed version: LibVNCServer 0.9.12; Siemens Simatic Itc1500 Firmware 3.2.1.0; Siemens Simatic Itc1500 Pro Firmware 3.2.1.0; Siemens Simatic Itc1900 Firmware 3.2.1.0; Siemens Simatic Itc1900 Pro Firmware 3.2.1.0; Siemens Simatic Itc2200 Firmware 3.2.1.0; Siemens Simatic Itc2200 Pro Firmware 3.2.1.0. Check the vendor advisory for mitigations.
References
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00020.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00028.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.html
- http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.html
- http://www.openwall.com/lists/oss-security/2020/06/30/3
- https://bugzilla.redhat.com/show_bug.cgi?id=1852356
- https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
- https://github.com/LibVNC/libvncserver/commit/aac95a9dcf4bbba87b76c72706c3221a842ca433
- 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/
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