CVE-2020-26247 | XXE in Nokogiri

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.

Published: 2020-12-30 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-26247 is rated Low Risk (31.8/100): CVSS Low severity, with medium exploitation likelihood (EPSS 1.11%). Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-26247

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-30 1.29% 1.11% -0.18%
2 2026-06-15 0.26% 1.29% +1.03%
3 2026-05-27 — 0.26% —

Full EPSS history (30 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-26247

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
2.6 3.1 LOW
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 1.2 1.4 [email protected]
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2020-26247

GitHub Security Advisory for CVE-2020-26247

GHSA-vr8q-g5c7-m54m · Severity: medium · Ecosystem: rubygems — Nokogiri::XML::Schema trusts input by default, exposing risk of XXE vulnerability

OS Trackers for CVE-2020-26247

vendor priority summary link
alpine medium CVE-2020-26247: 1 source package rows (ruby-nokogiri); 9 state rows across 7 repos (3.17-community, 3.18-community, 3.19-community, 3.20-community, 3.21-community, 3.22-community, edge-community); fixed 7, open 2. https://security.alpinelinux.org/vuln/CVE-2020-26247
debian low CVE-2020-26247 low priority: Debian including 1 source packages (ruby-nokogiri), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2020-26247
gentoo low CVE-2020-26247: 1 GLSA(s) (202208-29), 1 atom(s) (dev-ruby/nokogiri); latest impact low. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2020-26247
redhat medium — https://access.redhat.com/security/cve/CVE-2020-26247
suse medium CVE-2020-26247 severity moderate: SUSE including 311 source package names (amazon/suse-sles-15-sp1-chost-byos-v20210304-hvm-ssd-x86_64, amazon/suse-sles-15-sp1-chost-byos-v20220127-hvm-ssd-x86_64, …), 422 product×package rows across 44 product lines (HPE Helion OpenStack 8, Image SLES15-SP3-BYOS-Azure, … (44 product lines)): Known Affected 231, Fixed 191. https://www.suse.com/security/cve/CVE-2020-26247/
ubuntu medium CVE-2020-26247 medium priority: Ubuntu including 1 source packages (ruby-nokogiri), 15 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): not-affected 7, ignored 6, released 2. https://ubuntu.com/security/CVE-2020-26247

Affected software / configurations for CVE-2020-26247

Vendor Product Version Raw CPE
nokogiri nokogiri < 1.11.0 cpe:2.3:a:nokogiri:nokogiri:*:*:*:*:*:ruby:*:*
nokogiri nokogiri 1.11.0 cpe:2.3:a:nokogiri:nokogiri:1.11.0:rc1:*:*:*:ruby:*:*
nokogiri nokogiri 1.11.0 cpe:2.3:a:nokogiri:nokogiri:1.11.0:rc2:*:*:*:ruby:*:*
nokogiri nokogiri 1.11.0 cpe:2.3:a:nokogiri:nokogiri:1.11.0:rc3:*:*:*:ruby:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

References for CVE-2020-26247

cvelogic Threat Intelligence