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.
CVE-2017-18635
This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 4.8% (91st percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 6.1
- EG Score
- 6.1MEDIUMmedium confidence
- EG Risk
- 48EG Risk 48/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity61% × 45%Exploitation40% × 40%Automatability30% × 15%CISA SSVC: Track at low or medium mission impact; Track* or Attend at high (mission-essential systems).Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 4.8%
- EPSS %ILE
- 91st
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Track* or Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation public PoC (EG-KEV: elevated) · Automatable unknown (not published for this CVE) · Technical impact partial (CVSS below 9.0). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
September 25, 2019
Last Modified
November 21, 2024
References (20)
- cve@mitrehttps://access.redhat.com/errata/RHSA-2020:0754
- cve@mitrehttps://bugs.launchpad.net/horizon/+bug/1656435
- cve@mitrehttps://github.com/ShielderSec/cve-2017-18635
- cve@mitrehttps://github.com/novnc/noVNC/commit/6048299a138e078aed210f163111698c8c526a13#diff-286f7dc7b881e942e97cd50c10898f03L534
- cve@mitrehttps://github.com/novnc/noVNC/issues/748
- cve@mitrehttps://github.com/novnc/noVNC/releases/tag/v0.6.2
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2019/10/msg00004.html
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2021/12/msg00024.html
- cve@mitrehttps://usn.ubuntu.com/4522-1/
- cve@mitrehttps://www.shielder.it/blog/exploiting-an-old-novnc-xss-cve-2017-18635-in-openstack/
- af854a3a-2127-422b-91ae-364da2661108https://access.redhat.com/errata/RHSA-2020:0754
- af854a3a-2127-422b-91ae-364da2661108https://bugs.launchpad.net/horizon/+bug/1656435
- af854a3a-2127-422b-91ae-364da2661108https://github.com/ShielderSec/cve-2017-18635
- af854a3a-2127-422b-91ae-364da2661108https://github.com/novnc/noVNC/commit/6048299a138e078aed210f163111698c8c526a13#diff-286f7dc7b881e942e97cd50c10898f03L534
- af854a3a-2127-422b-91ae-364da2661108https://github.com/novnc/noVNC/issues/748
Vendor Advisories for CVE-2017-18635(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Patch Availability(3)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python-novnc (1:0.4+dfsg+1+20131010+gitf68af8af3d-4+deb8u1build0.16.04.1) @ xenial | 2026-05-27 | ubuntu |
| redhat | novnc-0:1.1.0-1.el8ost | 2020-08-04 | redhat |
| redhat | novnc-0:1.1.0-2.el7ost | 2020-03-10 | 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.
Affected Packages
(7 across 7 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| novnc | — |
| — |
Debian:12(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| novnc | — |
| — |
Debian:13(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| novnc | — |
| — |
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| novnc | — |
| — |
Debian:8(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| novnc | 1:0.4+dfsg+1+20131010+gitf68af8af3d-4 |
| — |
Debian:9(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| novnc | 1:0.4+dfsg+1+20131010+gitf68af8af3d-6 |
| — |
npm(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| @novnc/novnc | — |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Additional Vendor Advisories
(2)
Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.
Data Freshness Timeline
(refreshed 5× in last 7d / 20× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 140 total refreshes for this CVE.
- 2026-10-05 17:38 UTCEPSS rescore
- 2026-10-04 23:18 UTCEPSS rescore
- 2026-10-03 14:21 UTCEPSS rescore
- 2026-09-30 14:59 UTCEPSS rescore
- 2026-09-30 09:31 UTCEG score recompute
- 2026-09-28 13:45 UTCEPSS rescore
- 2026-09-27 18:43 UTCOSV refresh
- 2026-09-27 13:40 UTCEPSS rescore
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- 2026-09-11 09:31 UTCEPSS rescore
- 2026-09-08 03:52 UTCOSV refresh
- 2026-09-07 15:56 UTCEPSS rescore
- 2026-09-06 13:43 UTCEPSS rescore
- 2026-09-05 15:23 UTCEPSS rescore
- 2026-09-04 13:56 UTCEPSS rescore
- 2026-09-02 14:07 UTCEPSS rescore
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- 2026-09-01 03:31 UTCEPSS rescore
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- 2026-08-30 19:13 UTCEPSS rescore
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- 2026-08-21 23:44 UTCEPSS rescore
- 2026-08-21 14:14 UTCOSV refresh
- 2026-08-20 22:51 UTCEPSS rescore
- 2026-08-19 16:59 UTCEPSS rescore
- 2026-08-18 13:43 UTCEPSS rescore
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- 2026-08-06 13:42 UTCEPSS rescore
- 2026-08-06 00:51 UTCOSV refresh
- 2026-08-05 19:12 UTCEPSS rescore
- 2026-08-04 15:05 UTCEPSS rescore
- 2026-08-02 02:23 UTCEPSS rescore
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- 2026-07-30 16:24 UTCEPSS rescore
- 2026-07-30 01:26 UTCEPSS rescore
- 2026-07-28 15:32 UTCEPSS rescore
- 2026-07-23 14:15 UTCEPSS rescore
- 2026-07-23 01:28 UTCEG score recompute
- 2026-07-22 22:07 UTCEG score recompute
- 2026-07-22 14:04 UTCEPSS rescore
- 2026-07-22 14:04 UTCEPSS rescore
- 2026-07-21 15:21 UTCEPSS rescore
- 2026-07-21 15:21 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-20 05:40 UTCOSV refresh
- 2026-07-19 14:28 UTCEPSS rescore
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- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
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- 2026-07-16 16:59 UTCEPSS rescore
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- 2026-07-15 01:56 UTCEPSS rescore
- 2026-07-15 01:56 UTCEPSS rescore
- 2026-07-13 22:26 UTCEPSS rescore
- 2026-07-12 05:43 UTCEPSS rescore
- 2026-07-11 08:24 UTCEPSS rescore
- 2026-07-09 19:06 UTCEPSS rescore
- 2026-07-08 15:10 UTCEPSS rescore
- 2026-07-07 13:42 UTCEPSS rescore
- 2026-07-06 16:24 UTCEPSS rescore
- 2026-07-06 16:24 UTCEPSS rescore
- 2026-07-06 02:20 UTCEPSS rescore
- 2026-07-06 02:20 UTCEPSS rescore
- 2026-07-05 02:27 UTCEPSS rescore
- 2026-07-04 06:28 UTCEPSS rescore
- 2026-07-02 22:05 UTCOSV refresh
- 2026-07-02 16:54 UTCEPSS rescore
- 2026-07-01 15:02 UTCEPSS rescore
- 2026-06-30 23:19 UTCEPSS rescore
- 2026-06-30 23:19 UTCEPSS rescore
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- 2026-06-28 04:53 UTCEPSS rescore
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- 2026-06-21 14:54 UTCEPSS rescore
- 2026-06-21 01:57 UTCEPSS rescore
- 2026-06-21 01:57 UTCEPSS rescore
Publicly available exploits
(1 reference)Working exploit code is in the public domain (1 GitHub PoC). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.
- GitHub PoCShielderSec/CVE-2017-18635First seen Oct 16, 2019
PoC for CVE-2017-18635
Open source ↗
Related CVEs(same product + same vendor + same CWE)
Same vendor
7 shownredhat:RHSA-2020:3247
Frequently asked(5)
What is CVE-2017-18635?
When was CVE-2017-18635 disclosed?
Is CVE-2017-18635 actively exploited?
What is the CVSS score of CVE-2017-18635?
How do I remediate CVE-2017-18635?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2017-18635
Is Your Infrastructure Affected by CVE-2017-18635?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.