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No exploitation reportedFix available

CVE-2020-25708

No exploitation reported by the sources we read.

  • Published2020-11-27
  • WeaknessCWE-369

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw to send a specially crafted message that, when processed by the VNC server, would lead to a floating point exception, resulting in a denial of service.

Timeline

dates in UTC
  1. 2020-11-2718:15CVE publishedNVD

Versions per branch

NVD
Redhat enterprise linux
BranchAffectedFixed in
6.0= 6.0no fix published
7.0= 7.0no fix published
8.0= 8.0no fix published
Debian debian linux
BranchAffectedFixed in
10.0= 10.0no fix published
Libvncserver project libvncserver
BranchAffectedFixed in
0.9= 0.9.12no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • italcUbuntu:18.04:LTSall versions · no fixed version listedand 1 other package
  • italcUbuntu:16.04:LTSall versions · no fixed version listedand 1 other package
  • libvncserverUbuntu:20.04:LTSall versions · fixed in 0.9.12+dfsg-9ubuntu0.3
  • libvncserverUbuntu:18.04:LTSall versions · fixed in 0.9.11+dfsg-1ubuntu1.4
  • libvncserverUbuntu:16.04:LTSall versions · fixed in 0.9.10+dfsg-3ubuntu0.16.04.6
  • libvncserverRocky Linux:8all versions · fixed in 0:0.9.11-17.el8
  • libvncserverRed Hat:enterprise_linux:8::appstreamall versions · fixed in 0:0.9.11-17.el8and 2 other packages
  • libvncserverDebian:14all versions · fixed in 0.9.13+dfsg-1

60 more package ranges on OSV.dev

Vendor advisories

  • CVE-2020-25708 Red Hat Product Security31 products fixed · 12 known affected

    libvncserver: libvncserver/rfbserver.c has a divide by zero which could result in DoS

    libvncserver as a component of Red Hat Enterprise Linux 6 · libvncserver-devel as a component of Red Hat Enterprise Linux 6 · libvncserver.src as a component of Red Hat Enterprise Linux 6 · +9 more

  • RHSA-2021:1811 Red Hat Product Security31 products fixed

    Red Hat Security Advisory: libvncserver security update

Full record on NVD

Fix

  1. Vendor fix Red Hat Product Security RHSA-2021:1811 · 31 productsFor details on how to apply this update, which includes the changes described in this advisory, refer to: https://access.redhat.com/articles/11258
  2. No fix planned, says the vendor Red Hat Product Security CVE-2020-25708 · 10 productsOut of support scope
  3. No fix planned, says the vendor Red Hat Product Security CVE-2020-25708 · 2 productsWill not fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • NVDCVSS 3.17.5read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • CNAweakness (CWE)CWE-369known since 2026-10-23
  • NVDweakness (CWE)CWE-369read 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-11-08
  • OSVaffected packages—
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2020-11-27
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-3xcq-6vjj-wqx7

Frequently asked questions

What is CVE-2020-25708?

A divide by zero issue was found to occur in libvncserver-0.9.12. A malicious client could use this flaw to send a specially crafted message that, when processed by the VNC server, would lead to a floating point exception, resulting in a denial of service.

Is CVE-2020-25708 actively exploited?

Active exploitation of CVE-2020-25708 has not been confirmed. Its EPSS score was 1.5% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-25708?

CVE-2020-25708 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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