CVE-2026-79771 Nokogiri before 1.19.3 Memory Leak via XSLT Transform
Attackers can cause denial of service in applications using Nokogiri by triggering a memory leak via null bytes in XSLT transforms.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-79771?
CVE-2026-79771 is a medium-severity denial of service vulnerability in sparklemotion nokogiri, published on 25 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
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.
Weakness: CWE-401
Which versions are affected by CVE-2026-79771?
2 open source packages ship an affected version, including nokogiri. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
nokogiri RubyGems | All versions | 1.19.3 |
nokogiri RubyGems | All versions | 1.19.3 |
Products include Nokogiri Nokogiri.
How do I fix CVE-2026-79771?
Upgrade nokogiri to 1.19.3 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-79771 being exploited?
There is no known exploitation of CVE-2026-79771 in the wild and no public exploit code.
Other vulnerabilities in sparklemotion nokogiri
- CVE-2026-79770 Nokogiri before 1.19.3 ReDoS via CSS selector tokenizer
- CVE-2022-23476 Unchecked return value from xmlTextReaderExpand in Nokogiri
- CVE-2021-41098 Improper Restriction of XML External Entity Reference (XXE) in Nokogiri on JRuby
- CVE-2012-6685 Nokogiri is vulnerable to XML External Entity (XXE) attack
- CVE-2026-79772 Nokogiri before 1.19.1 Unchecked Return Value canonicalize
Sources
Also known as BELL-CVE-2026-79771, DEBIAN-CVE-2026-79771, GHSA-v2fc-qm4h-8hqv, MINI-2mqp-3f9p-m5q4, MINI-2xr9-5pxm-ccjg, MINI-3p7g-7gj8-wgwj and 7 more.