CVE-2026-7831

Katalog CVE

CVSS 7.6 · High EPSS 0,74%

Kerentanan Off-by-one Error pada uvnc ultravnc. Skor CVSS 3.1 7.6 (High) menurut CNA.

Deskripsi (NVD)

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.

Rincian

Terbit di NVD

1 Juli 2026

Terakhir diubah

9 Juli 2026

Status NVD

Modified

CVSS 3.1

7.6 (High), sumber CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:H · uraikan di kalkulator

Jenis kelemahan (CWE)

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

EPSS (30 hari)

0,74% peluang dieksploitasi; lebih tinggi dari 53,3% CVE lain

Produk dan versi terdampak

> Data dari konfigurasi CPE di NVD.

Referensi dan perbaikan

• https://github.com/ultravnc/UltraVNC product
• https://uvnc.com/ product · release notes
• https://www.securin.io/zero-days/cve-2026-7831-off-by-one-stack-overflow-viewer-namelength-ultravnc