CVE-2026-9675: undici WebSocket client vulnerable to denial of service via cumulative fragment bypass
CSIRTS triage
- What
- This vulnerability allows for denial of service via cumulative fragment bypass.
- Who is affected
- Users of the undici WebSocket client.
- Urgency
- Remediation is urgent due to high severity and potential for exploitation.
- Action
- Update to the patched version of the undici WebSocket client.
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-2026-9675
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-2026-96750.43% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 34% of all scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-9675 | coverage & exploitation status | NVD · CVE.org |
Same CVEs, other sources
How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.
- unknownMultiple vulnerabilities in Microsoft Azure Linux (June 29, 2026)cert-fr-avis
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