How severe is CVE-2017-7400?

CVE-2017-7400 has a CVSS score of 4.8/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2017-7400?

CVE-2017-7400 affects the following packages: horizon (PyPI), horizon (PyPI), horizon (PyPI). Ecosystems affected: PyPI.

How do I fix CVE-2017-7400?

Update horizon to 9.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-7400 is resolved across your whole dependency graph.

How do I detect CVE-2017-7400 in my PyPI dependencies?

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

How do I mitigate CVE-2017-7400 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-2017-7400 actively exploited in the wild?

No public exploit code has been indexed for CVE-2017-7400 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-2017-7400?

CVE-2017-7400 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 65th 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-2017-7400?

CVE-2017-7400 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-2017-7400 published, and has it been updated?

CVE-2017-7400 was published on April 3, 2017 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.

🐍

🐍 PyPI

Not in CISA KEV

MEDIUM severity

CVE-2017-7400 — horizon

MEDIUM

CVE-2017-7400 is a medium-severity (CVSS 4.8) Cross-site Scripting (XSS) vulnerability in horizon. A fix is available for horizon — see the affected versions and patch details below.

OpenStack Horizon Cross-site Scripting (XSS)

Also known asGHSA-47vp-44v9-rhgqPYSEC-2026-821

Published

Apr 3, 2017

Updated

Oct 24, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 7, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs65th percentile — riskier than 65% 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

3 pkgs affected

🐍horizon🐍horizon🐍horizon

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

Description

OpenStack Horizon 9.x through 9.1.1, 10.x through 10.0.2, and 11.0.0 allows remote authenticated administrators to conduct XSS attacks via a crafted federation mapping.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐍PyPI	`horizon`	≥ 9.0&&< 9.1.2	9.1.2`pip install --upgrade 'horizon==9.1.2'`
🐍PyPI	`horizon`	≥ 10.0&&< 10.0.3	10.0.3`pip install --upgrade 'horizon==10.0.3'`
🐍PyPI	`horizon`	≥ 11.0.0&&< 11.0.1	11.0.1`pip install --upgrade 'horizon==11.0.1'`

Affected Products

1 product · 19 configurations

Application

horizonopenstack

8 versions

9.0.09.0.19.1.09.1.110.0.010.0.110.0.211.0.0

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for horizon, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update horizon to 9.1.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-7400 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.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatLow

Product	Fixed in	Advisory
Red Hat OpenStack Platform 10.0 (Newton)	`python-django-horizon-1:10.0.3-6.el7ost`	RHSA-2017:1598
Red Hat OpenStack Platform 9.0 (Mitaka)	`python-django-horizon-1:9.0.1-13.el7ost`	RHSA-2017:1739

Frequently Asked Questions

OpenStack Horizon 9.x through 9.1.1, 10.x through 10.0.2, and 11.0.0 allows remote authenticated administrators to conduct XSS attacks via a crafted federation mapping.

O3 Security · Impact-Aware SCA

Is CVE-2017-7400 in your dependencies?

Find it across PyPI, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

4.8/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

High

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.0/AV:N/AC:L/PR:H/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

Apr 3, 2017

Last updated

Oct 24, 2026

Identifiers

CVE-2017-7400

GHSA-47vp-44v9-rhgq

PYSEC-2026-821

References

Advisorysecurityfocus.com Advisoryaccess.redhat.com · RHSA 2017:1598 Advisoryaccess.redhat.com · RHSA 2017:1739 Advisorynvd.nist.gov · CVE 2017 7400 Weblaunchpad.net Webopendev.org · 1407cfe53144146b29679de21f28c952282043ae Webopendev.org · 511b325b45b6bd7a88bb6df1a4639b80d0121277 Webopendev.org · a835dbfbaa2c70329c08d4b8429d49315dc6d651 Webopendev.org · ce80bb6fec3cb0262728e7ae8b9d695cf832e5bf

Related vulnerabilities

This CVE is medium severity, in line with the other 8 CVEs affecting horizon.

CVE-2026-55748CVE-2026-43002CVE-2022-45582CVE-2020-29565CVE-2012-2094CVE-2015-3219CVE-2012-2144CVE-2014-0157

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026