CVE-2026-57436: Nokogiri: Possible Use-After-Free when setting `Document#root=` to an invalid node type
CSIRTS triage
- What
- There is a possible use-after-free when setting Document#root to an invalid node type.
- Who is affected
- Deployments using Nokogiri.
- Urgency
- Remediation is medium urgency due to the medium severity rating.
- Action
- Apply the fix for CVE-2026-57436.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-57436
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-574360.40% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 34% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-57436 | coverage & exploitation status | NVD · CVE.org |