CRITICAL
libvncserver: Heap out-of-bound write inside structure in VNC client code allows for potential code execution
Published Dec 19, 2018
9.8
CRITICALCVSS 3.0
EPSS 8.62%
Description
LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution
Affected products
- Vendor n/a Product LibVNC Defaultn/a
- Version commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4dStatusaffectedConstraints-
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||
|---|---|---|---|---|---|---|---|---|---|
| n/a | LibVNC | n/a |
|
Configuration 1
- < 0.9.12
Configuration 2
OR
- 14.04
- 16.04
- 18.04
- 18.10
- 8.0
- 9.0
No data.
Red Hat Enterprise Linux 6
libvncserver
Will not fix
Red Hat Enterprise Linux 7
libvncserver
Will not fix
Red Hat Enterprise Linux 8
libvncserver
Will not fix
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | libvncserver | Will not fix | n/a |
| Red Hat Enterprise Linux 7 | libvncserver | Will not fix | n/a |
| Red Hat Enterprise Linux 8 | libvncserver | Will not fix | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
9.8 CRITICAL NVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High
1 other source (Red Hat) ▾
8.8 HIGH Red Hat
CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction Required
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High
7.5 HIGH NVD
AV:N/AC:L/Au:N/C:P/I:P/A:P
Access Vector Network
Access Complexity Low
Authentication None
Confidentiality Impact Partial
Integrity Impact Partial
Availability Impact Partial
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
8.62% 0.08622
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 2, 2026.
EPSS probability 0.08622
Score over time
2021–2026- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v1
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (26 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 2, 2026 | 8.62% (0.08622) | 94.95th | v5 (v2026.06.15) |
| Jun 15, 2026 | 8.66% (0.08659) | 94.41th | v5 (v2026.06.15) |
| Dec 28, 2025 | 21.03% (0.21030) | 95.46th | v4 (v2025.03.14) |
| Dec 27, 2025 | 16.35% (0.16354) | 94.67th | v4 (v2025.03.14) |
| Oct 28, 2025 | 21.29% (0.21289) | 95.43th | v4 (v2025.03.14) |
| Oct 27, 2025 | 16.57% (0.16570) | 94.65th | v4 (v2025.03.14) |
| Oct 1, 2025 | 21.60% (0.21597) | 95.56th | v4 (v2025.03.14) |
| Mar 30, 2025 | 16.83% (0.16827) | 94.39th | v4 (v2025.03.14) |
| Mar 29, 2025 | 26.90% (0.26895) | 94.18th | v4 (v2025.03.14) |
| Mar 17, 2025 | 16.83% (0.16827) | 94.44th | v4 (v2025.03.14) |
| Dec 17, 2024 | 10.51% (0.10509) | 95.01th | v3 (v2023.03.01) |
| Nov 28, 2024 | 7.63% (0.07627) | 94.41th | v3 (v2023.03.01) |
| Oct 28, 2024 | 11.53% (0.11527) | 95.39th | v3 (v2023.03.01) |
| Jul 14, 2024 | 13.25% (0.13248) | 95.61th | v3 (v2023.03.01) |
| Jun 20, 2024 | 14.29% (0.14290) | 95.75th | v3 (v2023.03.01) |
| Jun 1, 2024 | 14.57% (0.14569) | 95.77th | v3 (v2023.03.01) |
| May 11, 2024 | 18.28% (0.18278) | 96.17th | v3 (v2023.03.01) |
| Dec 13, 2023 | 21.66% (0.21656) | 95.98th | v3 (v2023.03.01) |
| Mar 7, 2023 | 28.13% (0.28130) | 96.09th | v3 (v2023.03.01) |
| Mar 6, 2023 | 9.80% (0.09801) | 94.34th | v2 (v2022.01.01) |
| Apr 1, 2022 | 9.80% (0.09801) | 93.83th | v2 (v2022.01.01) |
| Feb 4, 2022 | 9.80% (0.09801) | 87.26th | v2 (v2022.01.01) |
| Feb 3, 2022 | 5.33% (0.05330) | 78.84th | v1 |
| Jan 6, 2022 | 5.33% (0.05330) | 78.63th | v1 |
| Sep 1, 2021 | 5.33% (0.05330) | 88.23th | v1 |
| Apr 14, 2021 | 5.33% (0.05330) | 0.00th | v1 |
Weaknesses (2)
References (15)
- https://access.redhat.com/security/cve/CVE-2018-20020 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1661117 Issue Tracking
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-030-libvnc-heap-out-of-bound-write/ x_refsource_MISCThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2018/12/msg00017.html mailing-listx_refsource_MLISTMailing ListThird Party Advisory
- https://lists.debian.org/debian-lts-announce/2019/10/msg00042.html mailing-listx_refsource_MLIST
- https://lists.debian.org/debian-lts-announce/2019/11/msg00033.html mailing-listx_refsource_MLIST
- https://nvd.nist.gov/vuln/detail/CVE-2018-20020
- https://security.gentoo.org/glsa/201908-05 vendor-advisoryx_refsource_GENTOO
- https://security.gentoo.org/glsa/202006-06 vendor-advisoryx_refsource_GENTOO
- https://usn.ubuntu.com/3877-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://usn.ubuntu.com/4547-1/ vendor-advisoryx_refsource_UBUNTU
- https://usn.ubuntu.com/4547-2/ vendor-advisoryx_refsource_UBUNTU
- https://usn.ubuntu.com/4587-1/ vendor-advisoryx_refsource_UBUNTU
- https://www.cve.org/CVERecord?id=CVE-2018-20020
- https://www.debian.org/security/2019/dsa-4383 vendor-advisoryx_refsource_DEBIANThird Party Advisory
Change history (0)
No recorded changes yet.
Sources
CVE.org / MITRE
Status PUBLISHED
Assigner Kaspersky
Published Dec 19, 2018
Updated Aug 5, 2024
Reserved Dec 10, 2018
Link CVE-2018-20020
CISA Vulnrichment
Updated n/a