What is CVE-2026-7831?

CVE-2026-7831 is a high-severity vulnerability in Uvnc Ultravnc, classified under Off-by-one Error. CVSS score: 7.6/10. Published 2026-07-01.

How severe is CVE-2026-7831?

High severity. CVSS v3 base score is 7.6 out of 10.

Buffer overflow in Uvnc Ultravnc

CVE-2026-7831

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 st…

CVSS v3 metric

CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H.

Affected products

Uvnc Ultravnc — versions 0

Weakness classification (CWE)

CWE-193 — Off-by-one Error
CWE-787 — Out-of-bounds Write

References

33c584b5-0579-4c06-b2a0-8d8329fcab9c (vendor-advisory)
33c584b5-0579-4c06-b2a0-8d8329fcab9c (product)

Frequently asked questions

What is CVE-2026-7831?: CVE-2026-7831 is a high-severity vulnerability in Uvnc Ultravnc, classified under Off-by-one Error. CVSS score: 7.6/10. Published 2026-07-01.
How severe is CVE-2026-7831?: High severity. CVSS v3 base score is 7.6 out of 10.