CVE-2026-32853
LibVNCServer UltraZip Encoding Heap Out-of-bounds Read
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.
INFO
Published Date :
March 24, 2026, 6:16 p.m.
Last Modified :
March 25, 2026, 8:48 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 4.0 | MEDIUM | 83251b91-4cc7-4094-a5c7-464a1b83ea10 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update LibVNCServer to a fixed version.
- Apply commit 009008e to LibVNCServer.
- Validate the integrity of UltraZip encoding handler.
- Review server-side input validation.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-32853.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-32853 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-32853
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-32853 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-32853 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 25, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H Added CPE Configuration OR *cpe:2.3:a:libvncserver_project:libvncserver:*:*:*:*:*:*:*:* versions up to (excluding) 0.9.15 Added Reference Type VulnCheck: https://github.com/LibVNC/libvncserver/commit/009008e2f4d5a54dd71f422070df3af7b3dbc931 Types: Patch Added Reference Type VulnCheck: https://github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj Types: Vendor Advisory Added Reference Type VulnCheck: https://www.vulncheck.com/advisories/libvncserver-ultrazip-encoding-heap-out-of-bounds-read Types: Exploit, Vendor Advisory Added Reference Type CISA-ADP: https://github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 25, 2026
Action Type Old Value New Value Added Reference https://github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj -
New CVE Received by [email protected]
Mar. 24, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 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 Added CWE CWE-125 Added Reference https://github.com/LibVNC/libvncserver/commit/009008e2f4d5a54dd71f422070df3af7b3dbc931 Added Reference https://github.com/LibVNC/libvncserver/security/advisories/GHSA-87q7-v983-qwcj Added Reference https://www.vulncheck.com/advisories/libvncserver-ultrazip-encoding-heap-out-of-bounds-read