CVE-2026-7831
7.6 · HIGHOverview
CVE-2026-7831 is a high-severity vulnerability affecting uvnc ultravnc. It was published on July 1, 2026 and has a CVSS 3.1 base score of 7.6 (HIGH).
This vulnerability has a CVSS 3.1 base score of 7.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
Technical Description
UltraVNC viewer through 1.8.2.2 contains an off-by-one stack buffer overflow in the RFB ServerInit message handler. In vncviewer/ClientConnection.cpp, when the server-supplied nameLength equals exactly 2024 the code declares a 2024-byte stack buffer _dn[2024] and calls ReadString(_dn, 2024). ReadString writes the NUL terminator at buf[length], i.e., _dn[2024], one byte past the end of the stack buffer. A malicious VNC server can trigger this condition by advertising a desktop name of length 2024 in its ServerInit message. On release builds without stack canaries the single-byte NUL overwrite adjacent stack data. On builds with /GS stack protection the canary is corrupted and the process terminates, resulting in denial of service. User interaction (connecting the viewer to the malicious server) is required.
Remediation
Check the references section for vendor advisories and patches from uvnc. Update ultravnc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| uvnc | ultravnc | 0 | Affected |
Frequently Asked Questions
What is CVE-2026-7831?
CVE-2026-7831 is a high-severity vulnerability affecting uvnc ultravnc. It was published on July 1, 2026 and has a CVSS 3.1 base score of 7.6 (HIGH).
How severe is CVE-2026-7831?
This vulnerability has a CVSS 3.1 base score of 7.6, rated HIGH. It can be exploited remotely over the network. No authentication or special privileges are required for exploitation.
How do I fix or remediate CVE-2026-7831?
Check the references section for vendor advisories and patches from uvnc. Update ultravnc to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-7831?
CyberStrike's AI-powered security agents can automatically detect CVE-2026-7831 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
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