NIST deprecates RSA-2048 from 2030. Find every one of them before attackers do.
🐘
🐘 Packagist
Not in CISA KEV
MEDIUM severity

CVE-2020-25817 — framework

MEDIUM

CVE-2020-25817 is a medium-severity (CVSS 4.8) XML External Entity (XXE) vulnerability in silverstripe/framework. A fix is available for silverstripe/framework — see the affected versions and patch details below.

SilverStripe XXE Vulnerability in CSSContentParser

Also known asBIT-silverstripe-2020-25817GHSA-3vjc-5x79-m9r8
Published
Updated
Affected
1 pkg
Patched
1 / 1
Exploits
None indexed
Exploitation data as of Oct 23, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
0.8%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs57th percentile — riskier than 57% of all scored CVEsHighest risk
0.00%0.44%0.88%1.32%0.3%0.8%Apr 26Aug 26Oct 26

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
🐘silverstripe/framework

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

Description

SilverStripe through 4.6.0-rc1 has an XXE Vulnerability in CSSContentParser. A developer utility meant for parsing HTML within unit tests can be vulnerable to XML External Entity (XXE) attacks. When this developer utility is misused for purposes involving external or user submitted data in custom project code, it can lead to vulnerabilities such as XSS on HTML output rendered through this custom code. This is now mitigated by disabling external entities during parsing. (The correct CVE ID year is 2020 [CVE-2020-25817, not CVE-2021-25817]).

Affected Packages

1 total 1 fixed
EcosystemPackageVulnerable rangeFix
🐘Packagistsilverstripe/framework≥ 4.0.0&&< 4.7.44.7.4composer require silverstripe/framework:^4.7.4

Affected Products

1 product · 2 configurations
Application
silverstripesilverstripe
< 4.6.0
1 version
4.6.0

Detection & mitigation playbook

Open-source dependency

  1. Detect

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

  2. Fix

    Update silverstripe/framework to 4.7.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-25817 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.

Frequently Asked Questions

SilverStripe through 4.6.0-rc1 has an XXE Vulnerability in CSSContentParser. A developer utility meant for parsing HTML within unit tests can be vulnerable to XML External Entity (XXE) attacks. When this developer utility is misused for purposes involving external or user submitted data in custom project code, it can lead to vulnerabilities such as XSS on HTML output rendered through this custom code. This is now mitigated by disabling external entities during parsing. (The correct CVE ID year is 2020 [CVE-2020-25817, not CVE-2021-25817]).
O3 Security · Impact-Aware SCA

Is CVE-2020-25817 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works
CVE-2020-25817: framework XSS — Fixed in 4.7.4