XXE in Nokogiri
CVE-2020-26247
Nokogiri is a Rubygem providing HTML, XML, SAX, and Reader parsers with XPath and CSS selector support. In Nokogiri before version 1.11.0.rc4 there is an XXE vulnerability. XML Schemas parsed by Nokogiri::XML::Schema are trusted by default, allowing external resources to be accessed over the network, potentially enabling XXE or SSRF attacks. This behavior is counter to the security policy followed by Nokogiri maintainers, which is to treat all input as untrusted by default whenever possible. This is fixed in Nokogiri version 1.11.0.rc4.
Vulnerability class: XXE (XML External Entity)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 2.6 (Low). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.012 (66.5th percentile), scored .
Low probability of exploitation in the next 30 days, but still tracked. 66th percentile — 66.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.012 · newest: 0.012 · change: -0.000
Affected products
- Nokogiri — versions 1.11.0
- Sparklemotion Nokogiri — versions < 1.11.0.rc4
- Debian Linux — versions 9.0, 10.0
Weakness classification (CWE)
Public proof-of-concept exploits
References
- github.com/sparklemotion/nokogiri/security/advisories/GHSA-vr8q-g5c7-m54m (Third Party Advisory, Mitigation)
- rubygems.org/gems/nokogiri (Product, Third Party Advisory)
- hackerone.com/reports/747489 (Permissions Required)
- github.com/sparklemotion/nokogiri/releases/tag/v1.11.0.rc4 (Third Party Advisory, Release Notes)
- github.com/sparklemotion/nokogiri/commit/9c87439d9afa14a365ff13e73adc809cb2c3d9… (Patch, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2021/06/msg00007.html (mailing-list, Mailing List, Third Party Advisory)
- security.gentoo.org/glsa/202208-29 (vendor-advisory, Third Party Advisory)
- lists.debian.org/debian-lts-announce/2022/10/msg00018.html (mailing-list, Mailing List, Third Party Advisory)
Frequently asked questions
- What is CVE-2020-26247?
- CVE-2020-26247 is a low-severity vulnerability in Nokogiri, classified under Improper Restriction of XML External Entity Reference (XXE). CVSS score: 2.6/10. Published 2020-12-30.
- How severe is CVE-2020-26247?
- Low severity. CVSS v3 base score is 2.6 out of 10.
- Is CVE-2020-26247 known to be exploited?
- 3 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.