How severe is CVE-2020-2207?

CVE-2020-2207 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-2207?

CVE-2020-2207 affects the following packages: org.jenkins-ci.plugins:vncviewer (Maven). Ecosystems affected: Maven.

How do I fix CVE-2020-2207?

Update org.jenkins-ci.plugins:vncviewer to 1.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-2207 is resolved across your whole dependency graph.

How do I detect CVE-2020-2207 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:vncviewer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-2207 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2020-2207 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-2207 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-2207?

CVE-2020-2207 has an EPSS (Exploit Prediction Scoring System) score of 0.9%, placing it in the 59th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2020-2207?

CVE-2020-2207 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2020-2207 published, and has it been updated?

CVE-2020-2207 was published on July 2, 2020 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

MEDIUM severity

CVE-2020-2207 — vncviewer

MEDIUMFix: jenkinsci/vncviewer-plugin@99b2aa3

CVE-2020-2207 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in org.jenkins-ci.plugins:vncviewer. A fix is available for org.jenkins-ci.plugins:vncviewer — see the affected versions and patch details below.

Reflected XSS vulnerability in Jenkins VncViewer Plugin

Also known asGHSA-2j4h-cjgh-659v

Published

Jul 2, 2020

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 10, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.9%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs59th percentile — riskier than 59% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

☕org.jenkins-ci.plugins:vncviewer

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

VncViewer Plugin 1.7 and earlier does not escape a parameter value in the checkVncServ form validation endpoint output.

This results in a reflected cross-site scripting (XSS) vulnerability.

VncViewer Plugin 1.8 escapes the parameter value in the output.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.jenkins-ci.plugins:vncviewer`	all versions	1.8`org.jenkins-ci.plugins:vncviewer:1.8`

Affected Products

1 product · 1 configurations

Application

vncviewerjenkins

≤ 1.7

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.jenkins-ci.plugins:vncviewer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.jenkins-ci.plugins:vncviewer to 1.8 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-2207 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

VncViewer Plugin 1.7 and earlier does not escape a parameter value in the `checkVncServ` form validation endpoint output. This results in a reflected cross-site scripting (XSS) vulnerability. VncViewer Plugin 1.8 escapes the parameter value in the output.

O3 Security · Impact-Aware SCA

Is CVE-2020-2207 in your dependencies?

Find it across Maven, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

Timeline

Disclosed

Jul 2, 2020

Last updated

Oct 24, 2026

Identifiers

CVE-2020-2207

GHSA-2j4h-cjgh-659v

References

Advisoryopenwall.com Advisoryjenkins.io · 2020 07 02 Advisorynvd.nist.gov · CVE 2020 2207 Webgithub.com · 99b2aa3ed0857ef35de9a3aca0b0c53add3b392d Packagegithub.com · vncviewer plugin

Related vulnerabilities

This CVE is medium severity; 6 of 8 other CVEs with CWE-79 are rated as high or higher (top: high).

CVE-2026-126075CVE-2026-126063CVE-2026-110802CVE-2026-123364CVE-2026-118670CVE-2026-88986CVE-2026-63197CVE-2026-55649Browse all CWE-79

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026