Description
LibVNCServer 0.9.12 release and earlier contains heap buffer overflow vulnerability within the HandleCursorShape() function in libvncclient/cursor.c. An attacker sends cursor shapes with specially crafted dimensions, which can result in remote code execution.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| LibVNC | LibVNCServer | ≤ 0.9.12 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | libvncserver | 0.9.12+dfsg-9 | — |
| Debian 13 | libvncserver | 0.9.12+dfsg-9 | — |
| Debian 12 | libvncserver | 0.9.12+dfsg-9 | — |
| Debian 8 | libvncserver | 0.9.9+dfsg2-6.1+deb8u7 | DLA-2146-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | libvncserver | 0.9.12+dfsg-9ubuntu0.1 | USN-4407-1 |
| Ubuntu 18.04 LTS | libvncserver | 0.9.11+dfsg-1ubuntu1.2 | USN-4407-1 |
| Ubuntu 16.04 LTS | libvncserver | 0.9.10+dfsg-3ubuntu0.16.04.4 | USN-4407-1 |
| Ubuntu 14.04 LTS | x11vnc | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | libvncserver +1 | 0.9.11-9.el8_1.2 | RHSA-2020:0920 |
| RHEL 7 | libvncserver +1 | 0.9.9-14.el7_7 | RHSA-2020:0913 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8.0 E4S | libvncserver | 0.9.11-9.el8_0.2 | RHSA-2020:0921 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP1 | LibVNCServer | 0.9.10-4.14.1 | SUSE-SU-2020:1164-2, SUSE-SU-2020:1164-1 |
| SLES 12 SP5 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES 12 SP4 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES 12 SP3 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES 12 SP2 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
Show 13 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP1 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES 11 SP4 | LibVNCServer | 0.9.1-160.14.1 | SUSE-SU-2020:14355-1 |
| SLES for SAP 12 SP5 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES for SAP 12 SP4 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES for SAP 12 SP3 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES for SAP 12 SP2 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SLES for SAP 12 SP1 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SUSE OpenStack Cloud Crowbar 8 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SUSE OpenStack Cloud 8 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SUSE OpenStack Cloud 7 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SUSE Linux Enterprise Point of Sale 11 SP3 | LibVNCServer | 0.9.1-160.14.1 | SUSE-SU-2020:14355-1 |
| SUSE HPE Helion OpenStack 8 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
| SUSE Enterprise Storage 5 | LibVNCServer | 0.9.9-17.19.1 | SUSE-SU-2020:1165-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.1 | LibVNCServer | 0.9.10-lp151.7.3.1 | openSUSE-SU-2020:0624-1 |
Amazon Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Amazon Linux 2 | libvncserver +1 | 0.9.9-14.amzn2 | ALAS2-2020-1411 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | libvncserver +1 | 0.9.11-9.el8_1.2 | ELSA-2020-0920 |
| Oracle Linux 7 | libvncserver +1 | 0.9.9-14.el7_7 | ELSA-2020-0913 |
Advisories 15
- RHSA-2020:0921 Red Hat Security Advisory: libvncserver security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- RHSA-2020:0920 Red Hat Security Advisory: libvncserver security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- RHSA-2020:0913 Red Hat Security Advisory: libvncserver security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- USN-4407-1 libvncserver vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DLA-2146-1 libvncserver - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2020:14355-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1165-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:0624-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1164-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1164-2 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- ICSA-21-350-12 Siemens SIMATIC ITC CISA ICS & IT advisories · May 6, 2025
- SSA-390195 SSA-390195: LibVNC Vulnerabilities in SIMATIC ITC Products Siemens ProductCERT · Dec 14, 2021
- ALAS2-2020-1411 Important: libvncserver security update (Amazon Linux 2) Amazon Linux Security Center (ALAS) · Apr 23, 2020
- ELSA-2020-0913 Important: libvncserver security update (Oracle Linux 7) Oracle Linux Security Advisories (ELSA) · Mar 26, 2020
- ELSA-2020-0920 Important: libvncserver security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · Mar 23, 2020
References
- KLCERT-20-009: Remote Code Execution on LibVNC version prior to 0.9.12 third-party-advisory