Vulnerability · Published Aug 25, 2026 · Assigned by VulnCheck

CVE-2026-79771Nokogiri before 1.19.3 Memory Leak via XSLT Transform

Medium 5.3

In plain English

A medium-severity memory leak 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 0.4% (higher than 37% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium

Exploit odds (30 days)0.4%top 63.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Nokogiri versions before 1.19.3 contain a memory leak in the XSLT Stylesheet transform method when processing Ruby strings containing null bytes. Attackers can exploit this by passing attacker-controlled input with null bytes to transform parameters, causing heap allocations to leak and enabling denial of service against long-running processes.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
Debian:12	ruby-nokogiri	no fix listed	DEBIAN-CVE-2026-79771
Debian:13	ruby-nokogiri	no fix listed	DEBIAN-CVE-2026-79771
Debian:14	ruby-nokogiri	1.19.3+dfsg-1	DEBIAN-CVE-2026-79771
RubyGems	nokogiri	1.19.3	GHSA-v2fc-qm4h-8hqv
Ubuntu:24.04:LTS	ruby-nokogiri	no fix listed	UBUNTU-CVE-2026-79771
Ubuntu:26.04:LTS	ruby-nokogiri	no fix listed	UBUNTU-CVE-2026-79771

Affected products (as reported)

Vendor	Product	Versions
sparklemotion	nokogiri	0 – before 1.19.3

Weakness: CWE-401 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References

GitHub Security Advisory (GHSA-v2fc-qm4h-8hqv) vendor-advisory
VulnCheck Advisory: Nokogiri before 1.19.3 Memory Leak via XSLT Transform third-party-advisory