Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-79772Nokogiri before 1.19.1 Unchecked Return Value canonicalize

Medium 5.3

In plain English

A medium-severity security flaw in nokogiri from sparklemotion. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 28% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.3%top 72.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Nokogiri versions before 1.19.1 fail to check the return value from xmlC14NExecute in the canonicalize method, returning an empty string on failure instead of raising an exception. Attackers can exploit this to bypass signature validation in downstream SAML libraries by providing invalid canonicalized XML that is incorrectly accepted as valid.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	ruby-nokogiri	no fix listed	DEBIAN-CVE-2026-79772
Debian:13	ruby-nokogiri	no fix listed	DEBIAN-CVE-2026-79772
Debian:14	ruby-nokogiri	1.19.1+dfsg-1	DEBIAN-CVE-2026-79772
RubyGems	nokogiri	1.19.1	GHSA-wx95-c6cv-8532
Ubuntu:24.04:LTS	ruby-nokogiri	no fix listed	UBUNTU-CVE-2026-79772
Ubuntu:26.04:LTS	ruby-nokogiri	no fix listed	UBUNTU-CVE-2026-79772

Affected products (as reported)

Vendor	Product	Versions
sparklemotion	nokogiri	1.5.1 – before 1.19.1

Weakness: CWE-252 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

References

GitHub Security Advisory (GHSA-wx95-c6cv-8532) vendor-advisory
VulnCheck Advisory: Nokogiri before 1.19.1 Unchecked Return Value canonicalize third-party-advisory