CVE-2026-0989: Libxml2: unbounded relaxng include recursion leading to stack overflow
CSIRTS triage
- What
- RELAX NG schema validation allows unbounded recursion in include directives leading to stack overflow.
- Who is affected
- Applications parsing RELAX NG schemas from untrusted sources using Libxml2.
- Urgency
- Low priority; requires processing malicious schema input and stack overflow is a denial of service vector.
- Action
- Update Libxml2 to version with recursion depth limits in RELAX NG validation.
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-2026-0989
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-2026-09890.46% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 38% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-0989 | coverage & exploitation status | NVD · CVE.org |
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