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CVE-2026-32853

Libvncserver out-of-bounds read

8.1 HIGHPublic exploitEPSS 0.44%
  1. Published24 Mar 2026

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 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:H

Affected products

Libvncserver< 0.9.15

Remediation

Fixed in
Libvncserver≥ 0.9.15

References

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Frequently asked

Is CVE-2026-32853 being actively exploited?

CVE-2026-32853 is not in the CISA KEV catalog. A public exploit reference exists, so treat it as exploitable. Its EPSS exploit probability is 0.44%.

How severe is CVE-2026-32853?

CVE-2026-32853 has a CVSS 3.1 base score of 8.1, rated high. EPSS estimates a 0.44% probability of exploitation.

Which products are affected by CVE-2026-32853?

Affected products include Libvncserver.

How do I fix CVE-2026-32853?

Upgrade affected software to a fixed version, for example Libvncserver 0.9.15 or later, then confirm no affected versions remain in your inventory.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-32853 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.