HIGH
libvncserver: Use-after-free in file transfer extension server code allows for potential code execution
Published Dec 19, 2018
8.1
HIGHCVSS 3.0
EPSS 26.54%
Description
LibVNC before commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10b contains heap use-after-free vulnerability in server code of file transfer extension that can result remote code execution.
Affected products
- Vendor n/a Product LibVNC Defaultn/a
- Version commit ca2a5ac02fbbadd0a21fabba779c1ea69173d10bStatusaffectedConstraints-
- 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
Not affected
Red Hat Enterprise Linux 7
libvncserver
Not affected
Red Hat Enterprise Linux 8
libvncserver
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 6 | libvncserver | Not affected | n/a |
| Red Hat Enterprise Linux 7 | libvncserver | Not affected | n/a |
| Red Hat Enterprise Linux 8 | libvncserver | Not affected | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This issue did not affect the versions of libvncserver as shipped with Red Hat Enterprise Linux 6 and 7, as they did not include support for tightvnc file transfer.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
8.1 HIGH NVD
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity High
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High
1 other source (Red Hat) ▾
7.5 HIGH Red Hat
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Network
Attack Complexity High
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact High
Availability Impact High
6.8 MEDIUM NVD
AV:N/AC:M/Au:N/C:P/I:P/A:P
Access Vector Network
Access Complexity Medium
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.
26.54% 0.26543
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
EPSS probability 0.26543
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 (37 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 26.54% (0.26543) | 97.96th | v5 (v2026.06.15) |
| Sep 22, 2026 | 26.54% (0.26543) | 97.92th | v5 (v2026.06.15) |
| Sep 21, 2026 | 18.38% (0.18380) | 97.17th | v5 (v2026.06.15) |
| Sep 6, 2026 | 26.54% (0.26543) | 97.88th | v5 (v2026.06.15) |
| Sep 5, 2026 | 18.38% (0.18380) | 97.11th | v5 (v2026.06.15) |
| Aug 30, 2026 | 26.54% (0.26543) | 97.87th | v5 (v2026.06.15) |
| Aug 28, 2026 | 18.38% (0.18380) | 97.09th | v5 (v2026.06.15) |
| Aug 24, 2026 | 26.54% (0.26543) | 97.85th | v5 (v2026.06.15) |
| Aug 23, 2026 | 18.38% (0.18380) | 97.08th | v5 (v2026.06.15) |
| Jun 15, 2026 | 26.54% (0.26543) | 97.75th | v5 (v2026.06.15) |
| Dec 28, 2025 | 9.47% (0.09475) | 92.55th | v4 (v2025.03.14) |
| Dec 27, 2025 | 10.83% (0.10827) | 93.17th | v4 (v2025.03.14) |
| Oct 28, 2025 | 9.80% (0.09803) | 92.61th | v4 (v2025.03.14) |
| Oct 27, 2025 | 11.20% (0.11195) | 93.20th | v4 (v2025.03.14) |
| Oct 1, 2025 | 9.97% (0.09971) | 92.80th | v4 (v2025.03.14) |
| Mar 30, 2025 | 11.38% (0.11383) | 92.93th | v4 (v2025.03.14) |
| Mar 29, 2025 | 17.39% (0.17391) | 91.82th | v4 (v2025.03.14) |
| Mar 17, 2025 | 11.38% (0.11383) | 93.02th | v4 (v2025.03.14) |
| Feb 13, 2025 | 31.09% (0.31092) | 97.03th | v3 (v2023.03.01) |
| Dec 17, 2024 | 35.07% (0.35066) | 97.14th | v3 (v2023.03.01) |
| Nov 28, 2024 | 33.65% (0.33649) | 97.21th | v3 (v2023.03.01) |
| Oct 28, 2024 | 48.88% (0.48879) | 97.58th | v3 (v2023.03.01) |
| Jul 14, 2024 | 63.04% (0.63039) | 97.88th | v3 (v2023.03.01) |
| Jun 20, 2024 | 67.60% (0.67601) | 97.97th | v3 (v2023.03.01) |
| Jun 1, 2024 | 73.43% (0.73431) | 98.11th | v3 (v2023.03.01) |
| May 11, 2024 | 82.37% (0.82368) | 98.38th | v3 (v2023.03.01) |
| Apr 19, 2024 | 85.43% (0.85434) | 98.50th | v3 (v2023.03.01) |
| Feb 23, 2024 | 88.03% (0.88033) | 98.56th | v3 (v2023.03.01) |
| Dec 13, 2023 | 90.07% (0.90074) | 98.51th | v3 (v2023.03.01) |
| Mar 7, 2023 | 91.75% (0.91747) | 98.31th | v3 (v2023.03.01) |
| Mar 6, 2023 | 5.63% (0.05634) | 90.24th | v2 (v2022.01.01) |
| Apr 1, 2022 | 5.63% (0.05634) | 89.29th | v2 (v2022.01.01) |
| Feb 4, 2022 | 5.63% (0.05634) | 76.84th | v2 (v2022.01.01) |
| Feb 3, 2022 | 2.73% (0.02725) | 55.43th | v1 |
| Jan 6, 2022 | 2.73% (0.02725) | 54.99th | v1 |
| Sep 1, 2021 | 2.73% (0.02725) | 79.44th | v1 |
| Apr 14, 2021 | 2.73% (0.02725) | 0.00th | v1 |
Weaknesses (1)
References (10)
- https://access.redhat.com/security/cve/CVE-2018-6307 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1661136 Issue Tracking
- https://github.com/LibVNC/libvncserver/issues/241 Third Party Advisory
- https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-026-libvnc-heap-use-after-free/ 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://nvd.nist.gov/vuln/detail/CVE-2018-6307
- https://usn.ubuntu.com/3877-1/ vendor-advisoryx_refsource_UBUNTUThird Party Advisory
- https://www.cve.org/CVERecord?id=CVE-2018-6307
- https://www.debian.org/security/2019/dsa-4383 vendor-advisoryx_refsource_DEBIANThird Party Advisory
| Link | Providers | Tags |
|---|---|---|
| https://access.redhat.com/security/cve/CVE-2018-6307 | Vendor Advisory | |
| https://bugzilla.redhat.com/show_bug.cgi?id=1661136 | Issue Tracking | |
| https://github.com/LibVNC/libvncserver/issues/241 | Third Party Advisory | |
| https://ics-cert.kaspersky.com/advisories/klcert-advisories/2018/12/19/klcert-18-026-libvnc-heap-use-after-free/ | 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://nvd.nist.gov/vuln/detail/CVE-2018-6307 | ||
| https://usn.ubuntu.com/3877-1/ | vendor-advisoryx_refsource_UBUNTUThird Party Advisory | |
| https://www.cve.org/CVERecord?id=CVE-2018-6307 | ||
| 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 Jan 25, 2018
Link CVE-2018-6307
CISA Vulnrichment
Updated n/a