What’s Vulnerable › Vulnerabilities

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

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-08-25 · updated 2026-09-01
• Weakness: CWE-401

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 products

• sparklemotion nokogiri: before 1.19.3 — fixed in 1.19.3
• Rubygems Nokogiri: before 1.19.3; 1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4, 1.0.5 (+187) — fixed in 1.19.3

How to fix

Upgrade to a fixed version: sparklemotion nokogiri 1.19.3; Rubygems Nokogiri 1.19.3. Check the vendor advisory for mitigations.

References

• https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-v2fc-qm4h-8hqv
• https://www.vulncheck.com/advisories/nokogiri-before-memory-leak-via-xslt-transform

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