CVE-2018-21247

HIGHCVSS 7.5

7.5

An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function.

CVSS v3: 7.5
EG Score: —
EPSS: —
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/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
cve@mitrehttps://github.com/LibVNC/libvncserver/issues/253
cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY/
cve@mitrehttps://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/NVP7TJVYJDXDFRHVQ3ENEN3H354QPXEZ/
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/compare/LibVNCServer-0.9.12...LibVNCServer-0.9.13
af854a3a-2127-422b-91ae-364da2661108https://github.com/LibVNC/libvncserver/issues/253
af854a3a-2127-422b-91ae-364da2661108https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/4F6FUH4EFK4NAP6GT4TQRTBKWIRCZLIY/

Patch Availability(1)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
redhat	libvncserver-0:0.9.11-17.el8	2021-05-18	redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(2)

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

All Vendor Advisories

(1)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Red HatRHSA-2021:1811MODERATE2020-06-17
RHSA-2021:1811 — Moderate

Data Freshness Timeline

(refreshed 9× in last 7d / 9× 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.

2026-05-27 13:38 UTCepss_batch
2026-05-27 13:38 UTCepss_batch
2026-05-27 02:23 UTCEG score recompute
2026-05-27 02:23 UTCVendor advisory
2026-05-27 02:23 UTCGHSA enrichment
2026-05-26 13:42 UTCepss_batch
2026-05-26 13:42 UTCepss_batch
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(4)

What is CVE-2018-21247?

CVE-2018-21247 is a high vulnerability published on June 17, 2020. An issue was discovered in LibVNCServer before 0.9.13. There is an information leak (of uninitialized memory contents) in the libvncclient/rfbproto.c ConnectToRFBRepeater function.

When was CVE-2018-21247 disclosed?

CVE-2018-21247 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.

What is the CVSS score of CVE-2018-21247?

CVE-2018-21247 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2018-21247?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-21247, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2018-21247

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CVE-2018-21247

Published

Last Modified

References (16)

Patch Availability(1)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(4)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2018-21247?

Same vendor

Same CWE

CVE-2018-21247

📅 Published

🔄 Last Modified

🔗 References (16)

Patch Availability(1)

Weakness Classification(2)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(4)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2018-21247?

🔗 Related CVEs(same vendor + same CWE)

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References (16)

Frequently asked(4)

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