XXE in Silverstripe
CVE-2020-25817
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]).
Vulnerability class: XXE (XML External Entity)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.008 (55.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 55.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.008 · newest: 0.008 · change: 0.000
Affected products
- Silverstripe — versions 4.6.0
Weakness classification (CWE)
References
- www.silverstripe.org/download/security-releases/ (Vendor Advisory)
- www.silverstripe.org/blog/tag/release (Release Notes, Vendor Advisory)
- forum.silverstripe.org/c/releases (Release Notes, Vendor Advisory)
- www.silverstripe.org/download/security-releases/cve-2020-25817 (Broken Link)
Frequently asked questions
- What is CVE-2020-25817?
- CVE-2020-25817 is a medium-severity vulnerability in Silverstripe, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 4.8/10. Published 2021-06-08.
- How severe is CVE-2020-25817?
- Medium severity. CVSS v3 base score is 4.8 out of 10.