CVE-2026-57436 sparklemotion CVE debrief

Who should care

Defenders responsible for Ruby applications using the Nokogiri library should assess exposure and prioritize upgrading to Nokogiri version 1.19.4 or later. The vulnerability could lead to a heap use-after-free during garbage collection or finalization, potentially causing a segfault or invalid memory read. Defenders should review and update affected systems and applications, and monitor for potential exploitation attempts.

Why it matters

Defenders should care about CVE-2026-57436 because it affects the Nokogiri library for Ruby, potentially leading to a heap use-after-free during garbage collection or finalization, and requires verification and upgrading to Nokogiri version 1.19.4 or later.

• Potential for heap use-after-free during garbage collection or finalization
• Possible segfault or invalid memory read

Technical summary

The Nokogiri library for Ruby, prior to version 1.19.4, contains a vulnerability that allows a DTD node to be set as the document root, leading to a heap use-after-free during garbage collection or finalization. This vulnerability is fixed in Nokogiri version 1.19.4. The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. Defenders should prioritize verifying and upgrading to Nokogiri version 1.19.4 or later to mitigate this vulnerability. The vulnerability could lead to a potential segfault or invalid memory read.

Defensive priority

Defenders should prioritize verifying and upgrading to Nokogiri version 1.19.4 or later to mitigate this vulnerability.

Recommended defensive actions

• Verify Nokogiri version and upgrade to 1.19.4 or later
• Review and update affected systems and applications
• Monitor for potential exploitation attempts
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and NVD entry provide details on the vulnerability, including its description, CVSS score, and affected versions. The vulnerability is fixed in Nokogiri version 1.19.4. Defenders should verify and upgrade to Nokogiri version 1.19.4 or later to mitigate this vulnerability. The CVE record was published on 2026-06-25T15:16:41.163Z and has not been modified since then. The NVD entry provides additional information on the vulnerability, including its CVSS score and affected versions.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.