Description
An issue was discovered in LibVNCServer before 0.9.13. An improperly closed TCP connection causes an infinite loop in libvncclient/sockets.c.
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 | 0.9.13+dfsg-1 | — |
| Debian 13 | libvncserver | 0.9.13+dfsg-1 | — |
| Debian 12 | libvncserver | 0.9.13+dfsg-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 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | libvncserver | 0.9.12+dfsg-9ubuntu0.2 | USN-4434-1 |
| Ubuntu 20.04 LTS | veyon | No fix yet | — |
| Ubuntu 18.04 LTS | libvncserver | 0.9.11+dfsg-1ubuntu1.3 | USN-4434-1 |
| Ubuntu 16.04 LTS | libvncserver | 0.9.10+dfsg-3ubuntu0.16.04.5 | USN-4434-1 |
| Ubuntu 14.04 LTS | x11vnc | No fix yet | — |
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 14 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 11 SP4 | LibVNCServer | 0.9.1-160.19.1 | SUSE-SU-2020:14424-1 |
| 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 Linux Enterprise Point of Sale 11 SP3 | LibVNCServer | 0.9.1-160.19.1 | SUSE-SU-2020:14424-1 |
| 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 |
Advisories 9
- USN-4434-1 libvncserver vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- openSUSE-SU-2020:0988-1 Security update for LibVNCServer SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2020:14424-1 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
References
- https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
- https://github.com/LibVNC/libvncserver/commit/57433015f856cc12753378254ce4f1c78f5d9c7b
- openSUSE-SU-2020:0988 vendor-advisory
- openSUSE-SU-2020:1025 vendor-advisory
- openSUSE-SU-2020:1056 vendor-advisory
- USN-4434-1 vendor-advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf