XXE in Mozilla Firefox
CVE-2019-17020
If an XML file is served with a Content Security Policy and the XML file includes an XSL stylesheet, the Content Security Policy will not be applied to the contents of the XSL stylesheet. If the XSL sheet e.g. includes JavaScript, it would bypass any of the restrictions of the Content Security Policy applied to the XML document. This vulnerability affects Firefox < 72.
Vulnerability class: XXE (XML External Entity)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.011 (65.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 65th percentile — 65.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: -0.000
Affected products
- Mozilla Firefox — versions before 72
- Canonical Ubuntu Linux — versions 16.04, 18.04, 19.04
Weakness classification (CWE)
References
- bugzilla.mozilla.org/show_bug.cgi (Permissions Required)
- www.mozilla.org/security/advisories/mfsa2020-01/ (Vendor Advisory)
- usn.ubuntu.com/4234-1/ (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2019-17020?
- CVE-2019-17020 is a medium-severity vulnerability in Mozilla Firefox, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 6.5/10. Published 2020-01-08.
- How severe is CVE-2019-17020?
- Medium severity. CVSS v3 base score is 6.5 out of 10.