Description
An issue was discovered in LibVNCServer before 0.9.13. libvncclient/rfbproto.c does not limit TextChat size.
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 | — |
| Debian 9 | libvncserver | 0.9.11+dfsg-1.3~deb9u5 | DLA-2347-1 |
| Debian 8 | libvncserver | 0.9.9+dfsg2-6.1+deb8u8 | DLA-2264-1 |
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 | — |
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 |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.24 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.23 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.22 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.21 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.20 | libvncserver | 0.9.13-r0 | — |
Show 8 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.19 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.18 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.17 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.16 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.15 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.14 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.13 | libvncserver | 0.9.13-r0 | — |
| Alpine v3.12 | libvncserver | 0.9.13-r0 | — |
Oracle Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Oracle Linux 8 | libvncserver +1 | 0.9.11-17.el8 | ELSA-2021-1811 |
Advisories 9
- 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
- USN-4434-1 libvncserver vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- DLA-2347-1 libvncserver - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-2264-1 libvncserver - security update Debian Security (DSA / DLA) · Mar 9, 2026
- RLSA-2021:1811 Moderate: libvncserver security update Rocky Linux Security Advisories · Feb 4, 2026
- 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/commit/8937203441ee241c4ace85da687b7d6633a12365
- [debian-lts-announce] 20200630 [SECURITY] [DLA 2264-1] libvncserver security update mailing-list
- USN-4434-1 vendor-advisory
- [debian-lts-announce] 20200828 [SECURITY] [DLA 2347-1] libvncserver security update mailing-list
- https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf