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Not in CISA KEV
MEDIUM severity

CVE-2020-13258 — contentful

MEDIUM

CVE-2020-13258 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in contentful. 1 public exploit reference exists, so weaponization risk is real. A fix is available for contentful — see the affected versions and patch details below.

Cross-site scripting in Contentful

Also known asPYSEC-2026-626
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
1 known
Exploitation data as of Oct 8, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
2.1%probability of exploitation in next 30 days
Lower Risk+0.39%
Lower risk than most CVEs81th percentile — riskier than 81% of all scored CVEsHighest risk
0.49%1.46%2.42%3.39%2.8%1.0%1.7%2.1%Apr 26Jun 26Oct 26

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

How urgent is this, really

CVE-2020-13258 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.

Where this sits among everything scored

Of 385,738 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.

Real-World Exposure

1 pkg affected
🐍contentful

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

Contentful through 2020-05-21 for Python allows reflected XSS, as demonstrated by the api parameter to the-example-app.py.

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐍PyPIcontentfulall versions1.12.4pip install --upgrade 'contentful==1.12.4'

Affected Products

1 product · 1 configurations
Application
python examplecontentful
≤ 2020-05-21
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

Contentful through 2020-05-21 for Python allows reflected XSS, as demons…

github.comNVDMay 2020

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update contentful to 1.12.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-13258 is resolved across your whole dependency graph.

  3. 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.

How to detect CVE-2020-13258

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2020-13258 -u https://target
Template
Contentful <=2020-05-21 - Cross-Site Scripting
Severity
medium
Impact
Successful exploitation of this vulnerability could allow an attacker to execute malicious scripts in the context of the victim's browser, potentially leading to session hijacking, defacement, or theft of sensitive information.
Remediation
Upgrade Contentful to a version that is not vulnerable to CVE-2020-13258 or apply the necessary patches provided by the vendor.

Template by ProjectDiscovery nuclei-templates (pikpikcu), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

Contentful through 2020-05-21 for Python allows reflected XSS, as demonstrated by the api parameter to the-example-app.py.
O3 Security · Impact-Aware SCA

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CVE-2020-13258: contentful XSS — Fixed in 1.12.4