SB20260425205 - Stack-based buffer overflow in neatvnc

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Main Vulnerability Database SB20260425205

SB20260425205 - Stack-based buffer overflow in neatvnc

Published: April 25, 2026

Security Bulletin ID SB20260425205
CSH Severity
Medium
Patch available
YES
Number of vulnerabilities 1
Exploitation vector Remote access
Highest impact Denial of service

Breakdown by Severity

Medium 100%
  • Low
  • Medium
  • High
  • Critical

Description

This security bulletin contains information about 1 vulnerability.


1) Stack-based buffer overflow (CVE-ID: CVE-2026-42859)

CWE-ID: CWE-121 - Stack-based buffer overflow

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green


The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to stack-based buffer overflow in rsa_aes_send_challenge in src/auth/rsa-aes.c when handling an RSA-AES security type handshake with an oversized client RSA public key. A remote attacker can send a crafted security type 5 or 129 handshake to cause a denial of service.

The issue is pre-authentication and requires network reachability to the VNC listening socket.


Remediation

Install update from vendor's website.

References