CVE-2019-20840

HIGHNVD 7.57.5—

7.5

An issue was discovered in LibVNCServer before 0.9.13. libvncserver/ws_decode.c can lead to a crash because of unaligned accesses in hybiReadAndDecode.

CVSS v3: 7.5
EG Score: 7.5(medium)
EPSS: 86.7%
KEV: Not listed

Published

June 17, 2020

Last Modified

November 21, 2024

References (16)

cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.html
cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.html
cve@mitrehttp://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.html
cve@mitrehttps://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
cve@mitrehttps://github.com/LibVNC/libvncserver/commit/0cf1400c61850065de590d403f6d49e32882fd76
cve@mitrehttps://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY/
cve@mitrehttps://usn.ubuntu.com/4434-1/
af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00033.html
af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00055.html
af854a3a-2127-422b-91ae-364da2661108http://lists.opensuse.org/opensuse-security-announce/2020-07/msg00066.html
af854a3a-2127-422b-91ae-364da2661108https://cert-portal.siemens.com/productcert/pdf/ssa-390195.pdf
af854a3a-2127-422b-91ae-364da2661108https://github.com/LibVNC/libvncserver/commit/0cf1400c61850065de590d403f6d49e32882fd76
af854a3a-2127-422b-91ae-364da2661108https://github.com/LibVNC/libvncserver/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY/

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-06 13:45 UTCepss_batch
2026-06-06 13:45 UTCepss_batch
2026-06-05 22:45 UTCepss_batch
2026-06-05 22:45 UTCepss_batch
2026-06-05 06:08 UTCepss_batch
2026-06-05 06:08 UTCepss_batch
2026-06-04 13:10 UTCepss_batch
2026-06-04 13:10 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-06-01 13:50 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:14 UTCepss_batch
2026-05-31 00:14 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:38 UTCepss_batch
2026-05-27 02:23 UTCEG score recompute

Frequently asked(5)

What is CVE-2019-20840?

CVE-2019-20840 is a high vulnerability published on June 17, 2020. An issue was discovered in LibVNCServer before 0.9.13. libvncserver/ws_decode.c can lead to a crash because of unaligned accesses in hybiReadAndDecode.

When was CVE-2019-20840 disclosed?

CVE-2019-20840 was first published in the National Vulnerability Database on June 17, 2020, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2019-20840 actively exploited?

CVE-2019-20840 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 86.7% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2019-20840?

CVE-2019-20840 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2019-20840?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2019-20840, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2019-20840

📅 Published

🔄 Last Modified

🔗 References (16)

Weakness Classification(2)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2019-20840?

CVE-2019-20840

📅 Published

🔄 Last Modified

🔗 References (16)

Weakness Classification(2)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2019-20840?

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References (16)

Frequently asked(5)

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References (16)

Frequently asked(5)

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