Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-79769Nokogiri before 1.19.4 Invalid Memory Read via initialize_copy_with_args

Medium 5.5

In plain English

A medium-severity type confusion 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 24% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.5Medium

Exploit odds (30 days)0.3%top 76.4% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Nokogiri versions before 1.19.4 contain a possible invalid (out-of-bounds) memory read in the protected internal Node#initialize_copy_with_args helper behind Node#dup and #clone, which unwrapped its source argument as an xmlNode without a type check. If application code calls this protected method with a non-Node argument (e.g., a Namespace), it reads an xmlNs out of bounds, crashing the process. This is only triggerable by a programming error and cannot be triggered by untrusted input or normal use of the public API. Only CRuby is affected. Version 1.19.4 adds a type check and raises TypeError.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:13	ruby-nokogiri	no fix listed	DEBIAN-CVE-2026-79769
Debian:14	ruby-nokogiri	1.19.4+dfsg-1	DEBIAN-CVE-2026-79769
Ubuntu:24.04:LTS	ruby-nokogiri	no fix listed	UBUNTU-CVE-2026-79769
Ubuntu:26.04:LTS	ruby-nokogiri	no fix listed	UBUNTU-CVE-2026-79769

Affected products (as reported)

Vendor	Product	Versions
sparklemotion	nokogiri	0 – before 1.19.4

Weakness: CWE-843 · Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

References

GitHub Security Advisory (GHSA-g9g8-vgvw-g3vf) vendor-advisory
VulnCheck Advisory: Nokogiri before 1.19.4 Invalid Memory Read via initialize_copy_with_args third-party-advisory