Medium severity · published Jun 25, 2026
CVE-2026-57436
Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type
5.3
CVSS
0.4%
EPSS
No
On KEV
Description
Nokogiri is an open source XML and HTML library for the Ruby programming language. Prior to 1.19.4, Nokogiri::XML::Document#root= validated only that the new root was a Nokogiri::XML::Node, allowing a DTD node to be set as the document root. The result is a heap use-after-free during garbage collection or finalization, leading to an invalid memory read or potentially a segfault. This vulnerability is fixed in 1.19.4.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 34% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
NO
nokogiri · sparklemotion
< 1.19.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-57436
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-57436
Mitigation
https://github.com/sparklemotion/nokogiri/security/advisories/GHSA-wjv4-x9w8-wm3h
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