CVE-2020-25817 SilverStripe XXE Vulnerability in CSSContentParser

What is CVE-2020-25817?

CVE-2020-25817 is a medium-severity vulnerability in Silverstripe Silverstripe, published on 8 Jun 2021. An attacker needs administrator access to exploit it, and only if a user opens a file or follows a link.

Official 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]).

Weakness: CWE-611

Which versions are affected by CVE-2020-25817?

3 open source packages ship an affected version, including silverstripe/framework and silverstripe. It affects 1 product.

Products include Silverstripe Silverstripe.

How do I fix CVE-2020-25817?

Upgrade silverstripe/framework to 4.7.4 or later.

Is CVE-2020-25817 being exploited?

There is no known exploitation of CVE-2020-25817 in the wild and no public exploit code.

Other vulnerabilities in Silverstripe Silverstripe

• CVE-2007-2321 Other in n/a Critical 10.0
• CVE-2019-12204 Missing warning can lead to unauthenticated admin access in SilverStripe Critical 9.8
• CVE-2019-5715 Silverstripe Framework SQLi Vulnerability Critical 9.8
• CVE-2019-12437 Silverstripe CSRF Protection Bypass via GraphQL High 8.8
• CVE-2020-6164 Silverstripe CMS information disclosure High 7.5

All Silverstripe Silverstripe vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-silverstripe-2020-25817, GHSA-3vjc-5x79-m9r8.