CVE-2026-32853

MEDIUM EPSS 35.0%
Published Mar 24, 20263mo ago · Modified Jun 17, 20261w ago
6.9 CVSS 4.0
Medium
Find Similar
Published Mar 24, 2026 3mo ago
Last Modified Jun 17, 2026 1w ago

Description

LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the HandleUltraZipBPP() function by manipulating subrectangle header counts to read beyond the allocated heap buffer.

CVSS Details

Base Score
6.9
Exploitability
—
Impact
—
Vector string
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
35.0% percentile
Exploit & Patch Status
Public Exploit Known
Patch Available

Weaknesses 1

CWE-125 Out-of-bounds Read Memory Safety

Affected Products 1

VendorProductVersionRange
libvncserver_projectlibvncserver* <0.9.15

References 3

  • github.com https://github.com/LibVNC/libvncserver/commit/009008e2f4d5a54dd71f422070df3af7b3dbc931
    Patch
  • github.com https://github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj
    Vendor Advisory
  • vulncheck.com https://www.vulncheck.com/advisories/libvncserver-ultrazip-encoding-heap-out-of-bounds-read
    ExploitVendor Advisory

Remediation

  • github.com https://github.com/LibVNC/libvncserver/commit/009008e2f4d5a54dd71f422070df3af7b3dbc931
    Patch