CVE-2026-57436: Nokogiri is an open source XML and HTML library for the Ruby programming language

Q: How do I fix CVE-2026-57436?

nokogiri: upgrade to 1.19.4. Exact commands for each OS are on this page.

Q: Is CVE-2026-57436 being exploited?

CVE-2026-57436 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-57436 affect?

CVE-2026-57436 affects nokogiri. Severity is medium (CVSS 5.3). Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root

Q: How urgent is CVE-2026-57436?

Priority 32/100. Remotely exploitable, no login, no user action

Routine

MEDIUM 5.3REMOTEUPGRADE

CVE-2026-57436 is a medium-severity flaw (CVSS 5.3) affecting nokogiri. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 66%)
CISA exploited list	No
Weakness	CWE-416
Published	2026-06-25
Last modified	2026-10-25

Publisher (CNA): GitHub, Inc. · Vendor: nokogiri

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-25 15:16 UTCPublished CVE record published
2026-10-25 23:10 UTCUpdated Record last modified

nokogiri nokogiri UPGRADE

Affected: < 1.19.4

Fixed in: 1.19.4

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy nokogiri || rpm -q nokogiri || nokogiri --version

2. UPGRADE to 1.19.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade nokogiri

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade nokogiri

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-57436?

nokogiri: upgrade to 1.19.4. Exact commands for each OS are on this page.

Is CVE-2026-57436 being exploited?

CVE-2026-57436 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-57436 affect?

CVE-2026-57436 affects nokogiri. Severity is medium (CVSS 5.3). Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root

How urgent is CVE-2026-57436?

Priority 32/100. Remotely exploitable, no login, no user action

Software pages

Ruby vulnerabilities

Related CVEs

CVE-2026-57235 HIGH 8.2 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57236 HIGH 8.2 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57434 HIGH 7.5 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57435 HIGH 7.5 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language
CVE-2026-57437 MEDIUM 5.3 UPGRADE Nokogiri is an open source XML and HTML library for the Ruby programming language

References

← Back to latest CVEs