CVE-2026-32853: LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerabili

Q: How do I fix CVE-2026-32853?

libvncserver: upgrade to 0.9.15. Exact commands for each OS are on this page.

Q: Is CVE-2026-32853 being exploited?

CVE-2026-32853 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-32853 affect?

CVE-2026-32853 affects libvncserver. Severity is high (CVSS 8.1). 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. Attac

Q: How urgent is CVE-2026-32853?

Priority 43/100. High severity; Public exploit reference

This month

HIGH 8.1UPGRADE

CVE-2026-32853 is a high-severity flaw (CVSS 8.1) affecting libvncserver. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

High severity
Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.4% (top 61%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-03-24
Last modified	2026-07-14

Publisher (CNA): VulnCheck · Vendor: libvncserver project

Last updated 2026-07-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-03-24 18:16 UTCPublished CVE record published
2026-07-14 19:16 UTCUpdated Record last modified

libvncserver project libvncserver UPGRADE

Affected: < 0.9.15

Fixed in: 0.9.15

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy libvncserver || rpm -q libvncserver || libvncserver --version

2. UPGRADE to 0.9.15 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade libvncserver

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade libvncserver

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-32853?

libvncserver: upgrade to 0.9.15. Exact commands for each OS are on this page.

Is CVE-2026-32853 being exploited?

CVE-2026-32853 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-32853 affect?

CVE-2026-32853 affects libvncserver. Severity is high (CVSS 8.1). 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. Attac

How urgent is CVE-2026-32853?

Priority 43/100. High severity; Public exploit reference

Related CVEs

CVE-2026-32854 HIGH 7.5 UPGRADE LibVNCServer versions 0.9.15 and prior (fixed in commit dc78dee) contain null pointer dereference vulnerabilit

References

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