Description
An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function.
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 | 0.9.11+dfsg-1.2 | — |
| Debian 13 | libvncserver | 0.9.11+dfsg-1.2 | — |
| Debian 12 | libvncserver | 0.9.11+dfsg-1.2 | — |
| Debian 9 | libvncserver | 0.9.11+dfsg-1.3~deb9u1 | DSA-4383-1 |
| Debian 8 | libvncserver | 0.9.9+dfsg2-6.1+deb8u4 | DLA-1617-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | veyon | No fix yet | — |
| Ubuntu 26.04 LTS | veyon | No fix yet | — |
| Ubuntu 25.10 | veyon | No fix yet | — |
| Ubuntu 24.04 LTS | veyon | No fix yet | — |
| Ubuntu 22.04 LTS | veyon | No fix yet | — |
Show 7 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | veyon +1 | No fix yet | — |
| Ubuntu 18.04 LTS | libvncserver | No fix yet | — |
| Ubuntu 16.04 LTS | libvncserver | No fix yet | — |
| Ubuntu 14.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 20.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 18.04 LTS | x11vnc | No fix yet | — |
| Ubuntu Pro 16.04 LTS | x11vnc | No fix yet | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 8 | libvncserver +1 | 0.9.11-17.el8 | RHSA-2021:1811 |
AlmaLinux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux 8 | libvncserver +1 | 0.9.11-17.el8 | ALSA-2021:1811 |
Rocky Linux
Errata ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Rocky Linux 8 | libvncserver | 0.9.11-17.el8 | RLSA-2021:1811 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP2 | LibVNCServer | 0.9.10-4.22.1 | SUSE-SU-2020:1922-1 |
| SLES 15 SP1 | LibVNCServer | 0.9.10-4.22.1 | SUSE-SU-2020:1922-1 |
| SLES 12 SP5 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SLES 12 SP4 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SLES 12 SP3 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
Show 12 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 SP2 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SLES for SAP 12 SP5 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SLES for SAP 12 SP4 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SLES for SAP 12 SP3 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SLES for SAP 12 SP2 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE OpenStack Cloud Crowbar 9 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE OpenStack Cloud Crowbar 8 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE OpenStack Cloud 9 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE OpenStack Cloud 8 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE OpenStack Cloud 7 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE HPE Helion OpenStack 8 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
| SUSE Enterprise Storage 5 | LibVNCServer | 0.9.9-17.31.1 | SUSE-SU-2020:2167-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 15.2 | LibVNCServer | 0.9.10-lp152.9.4.2 | openSUSE-SU-2020:1056-1, openSUSE-SU-2020:1025-1 |
| openSUSE Leap 15.1 | LibVNCServer | 0.9.10-lp151.7.9.1 | openSUSE-SU-2020:0988-1 |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | libvncserver +1 | 0.9.11-17.el8 | ELSA-2021-1811 |
Advisories 13
- ALSA-2021:1811 Moderate: libvncserver security update AlmaLinux Security Advisories · Oct 29, 2026
- RHSA-2021:1811 Red Hat Security Advisory: libvncserver security update Red Hat Security Advisories (RHSA) · Jun 27, 2026
- DSA-4383-1 libvncserver - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1617-1 libvncserver - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2021:1811 Moderate: libvncserver security update Rocky Linux Security Advisories · Feb 4, 2026
- openSUSE-SU-2020:0988-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:2167-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1025-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:1922-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2020:1056-1 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
- ELSA-2021-1811 Moderate: libvncserver security update (Oracle Linux 8) Oracle Linux Security Advisories (ELSA) · May 25, 2021
References
- https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
- https://github.com/LibVNC/libvncserver/issues/253
- FEDORA-2020-37112ac660 vendor-advisory
- FEDORA-2020-1a4b1c8271 vendor-advisory
- openSUSE-SU-2020:0988 vendor-advisory
- openSUSE-SU-2020:1025 vendor-advisory
- openSUSE-SU-2020:1056 vendor-advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf