CVE-2019-20382

Host memory exhaustion via VNC disconnect leak

Published Mar 5, 2020 · Updated Aug 5, 2024

Memory leak in QEMU 4.1.0 allows remote authenticated users to exhaust host memory by disconnecting from a VNC server. zrle_compress_data initializes libz state on a local VncState, but vnc_zrle_clear passes the connection VncState to deflateEnd, which returns Z_STREAM_ERROR without freeing the allocation. Reachability requires VNC access with ZRLE or Tight encoding enabled; repeated disconnects consume host memory until resource exhaustion interrupts service.

CVSS severity3.5
Low
EPSS probability0.87%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in QEMU 4.1.0 allows remote authenticated users to exhaust host memory by disconnecting from a VNC server. zrle_compress_data initializes libz state on a local VncState, but vnc_zrle_clear passes the connection VncState to deflateEnd, which returns Z_STREAM_ERROR without freeing the allocation. Reachability requires VNC access with ZRLE or Tight encoding enabled; repeated disconnects consume host memory until resource exhaustion interrupts service.

The record

CVE
CVE-2019-20382
Published
Mar 5, 2020
Updated
Aug 5, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-401, T1499.003
Attack vector
adjacent
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 5, 2020CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

3.5NIST NVDCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
3.5UbuntuCVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
2.7NIST NVDAV:A/AC:L/Au:S/C:N/I:N/A:P

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectoradjacent
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-401Missing Release of Memory after Effective Lifetime
T1499.003Endpoint Denial of Service: Application Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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