What’s Vulnerable › Vulnerabilities
CVE-2018-20748
- Severity: critical (CVSS 9.8 v3.1)
- Exploited in the wild: not listed in CISA KEV
- EPSS: 3.3% probability of exploitation in the next 30 days
- Public exploit or detection template: yes
- Published: 2019-01-30 · updated 2026-06-17
- Weakness: CWE-787
Description
LibVNC before 0.9.12 contains multiple heap out-of-bounds write vulnerabilities in libvncclient/rfbproto.c. The fix for CVE-2018-20019 was incomplete.
Affected products
- Canonical Ubuntu Linux: 14.04, 16.04, 18.04, 18.10
- Debian Linux: 8.0
- Libvnc Project Libvncserver: before 0.9.12 — fixed in 0.9.12
- 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: Libvnc Project 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
- https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
- https://github.com/LibVNC/libvncserver/commit/a64c3b37af9a6c8f8009d7516874b8d266b42bae
- https://github.com/LibVNC/libvncserver/commit/c2c4b81e6cb3b485fb1ec7ba9e7defeb889f6ba7
- https://github.com/LibVNC/libvncserver/commit/c5ba3fee85a7ecbbca1df5ffd46d32b92757bc2a
- https://github.com/LibVNC/libvncserver/commit/e34bcbb759ca5bef85809967a268fdf214c1ad2c
- https://github.com/LibVNC/libvncserver/issues/273
- https://lists.debian.org/debian-lts-announce/2019/01/msg00029.html
- https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html
- https://usn.ubuntu.com/3877-1/
- https://usn.ubuntu.com/4547-1/
- https://usn.ubuntu.com/4587-1/
- https://www.openwall.com/lists/oss-security/2018/12/10/8
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