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Fencer Vulns
medium 6.1

CVE-2017-18635 json

Cross-Site Scripting in @novnc/novnc

published 2019-09-25 7 y ago modified 2026-06-17 4 mo ago also GHSA-49rv-g7w5-m8xx , EUVD-2020-0588

cvss
6.1
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.8%
EPSS 4.8% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

An XSS vulnerability was discovered in noVNC before 0.6.2 in which the remote VNC server could inject arbitrary HTML into the noVNC web page via the messages propagated to the status field, such as the VNC server name.

Patch / fix

  • npm @novnc/novnc 0.6.2
  • novnc novnc 0.6.2
  • novnc Debian 14, Debian 13, Debian 12 1:1.0.0-1

debian advisories DEBIAN-CVE-2017-18635

  • novnc Ubuntu 16.04 LTS 1:0.4+dfsg+1+20131010+gitf68af8af3d-4+deb8u1build0.16.04.1

ubuntu advisories UBUNTU-CVE-2017-18635

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • rhvm rhev manager 4.4 4.4.1.8-0.7.el8ev
  • novnc rhev manager 4.4 1.1.0-1.el8ost
  • ovirt-engine rhev manager 4.4 4.4.1.8-0.7.el8ev
  • rhvm-dependencies rhev manager 4.4 4.4.0-1.el8ev
  • ovirt-engine-setup rhev manager 4.4 4.4.1.8-0.7.el8ev
  • ovirt-engine-tools rhev manager 4.4 4.4.1.8-0.7.el8ev
  • ovirt-engine-backend rhev manager 4.4 4.4.1.8-0.7.el8ev
  • ovirt-engine-restapi rhev manager 4.4 4.4.1.8-0.7.el8ev

red hat advisories RHSA-2020:3247RHSA-2020:0754

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2017-18635 updated cvss 6.1

novnc: XSS vulnerability via the messages propagated to the status field

  • Red Hat OpenStack Platform 10 (Newton) novnc, openstack-nova-novncproxy
    affected: workaround, no fix planned “There is no known mitigation for this issue, the flaw can only be resolved by applying updates.”
  • Red Hat OpenStack Platform 14 (Rocky) novnc, openstack-nova-novncproxy
    affected: workaround, no fix available “There is no known mitigation for this issue, the flaw can only be resolved by applying updates.”
  • Red Hat OpenStack Platform 13.0 novnc 1.1.0-2.el7ost Red Hat OpenStack Platform 13.0 for RHEL 7.6 EUS Server novnc 1.1.0-2.el7ost
    fixed: vendor fix “There is no known mitigation for this issue, the flaw can only be resolved by applying updates.” RHSA-2020:0754
  • Red Hat RHEL-8-RHEV-S-4.4 - Red Hat Virtualization Engine 4.4 novnc 1.1.0-1.el8ost
    fixed: vendor fix “There is no known mitigation for this issue, the flaw can only be resolved by applying updates.” RHSA-2020:3247
  • Red Hat OpenStack Platform 15 (Stein) novnc, openstack-nova-novncproxy Red Hat RHEL-8-RHEV-S-4.4 - Red Hat Virtualization Engine 4.4 snmp4j 2.4.1-1.el8ev, xmlrpc 3.1.3-1.el8ev, makeself 2.4.0-4.el8ev, rhvm 4.4.1.8-0.7.el8ev, log4j12 1.2.17-22.el8ev, m2crypto 0.35.2-5.el8ev, +119 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.79% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • shielder.it https://www.shielder.it/blog/exploiting-an-old-novnc-xss-cve-2017-18635-in-openstack/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
npm @novnc/novnc
<0.6.2
0.6.2

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.