Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11…
Priority MEDIUM 49CWE-119Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Will not fix Red Hat: no fix planned
Attack profile from CVSS 3.0 · NVD. Fix status from CNA and Red Hat. Impact type from CWE-119 and the CVSS impact.
Summary
Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted FramebufferUpdate message with the Ultra type tile, such that the LZO payload decompressed length exceeds what is specified by the tile dimensions.
Why it matters now
EPSS 0.0382 90th percentileScored 2026-11-07
Fix Will not fix Red Hat: no fix planned
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:libvncserver_project:libvncserver:0.9.10:*:*:*:*:*:*:* | 0.9.10 | Vulnerable | Libvncserver Project |
- cpe:2.3:a:libvncserver_project:libvncserver:0.9.10:*:*:*:*:*:*:* Versions 0.9.10 Vulnerable ·Libvncserver Project
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 6 | Affected | No fix planned: Will not fix |
| Red Hat Enterprise Linux 7 | Affected | No fix planned: Will not fix |
Timeline
- 2026-10-02 Threatist record created from CVE-2016-9942
- 2026-10-03 Alias added: GHSA-wx7p-737c-9wqw
- 2026-10-21 EPSS moved to the 90th–95th percentile
- 2026-10-25 EPSS moved to the 50th–90th percentile
- 2026-10-27 EPSS moved to the 90th–95th percentile
References
More Libvncserver Project Libvncserver vulnerabilities
- TI-2026-25316 LibVNCServer UltraZip Encoding Heap Out-of-bounds Read CVSS 4.0MEDIUM 6.9
- TI-2026-25317 LibVNCServer httpd proxy NULL Pointer Dereference CVSS 4.0MEDIUM 6.3
- TI-2018-05234 An issue was discovered in LibVNCServer through 0.9.11. CVSS 3.0CRITICAL 9.8
- TI-2016-08053 Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer before 0.9.11… CVSS 3.0CRITICAL 9.8
- TI-2017-14070 It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly… CVSS 3.1CRITICAL 9.8
- TI-2020-11267 An issue was discovered in LibVNCServer before 0.9.13. CVSS 3.1HIGH 7.5
Sources
- CVE-2016-9942 · CVE Program
- CVE-2016-9942 · NVD
- FIRST EPSS
- GHSA-wx7p-737c-9wqw · GitHub Advisory Database · CC BY 4.0
- CVE-2016-9942 · Red Hat security data · CC BY 4.0
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