CVE-2026-53221
CSIRTS triage
- What
- The vulnerability involves incorrect tunnel matching in the vti6_tnl_lookup function.
- Who is affected
- Deployments using the affected ip6_vti functionality.
- Urgency
- Remediation is medium due to the severity rating of 5.5.
- Action
- Apply the patch for CVE-2026-53221.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.56% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 43% of all EPSS-scored CVEs.
Advisory coverage (1)
- mediumCVE-2026-53221: ip6_vti: fix incorrect tunnel matching in vti6_tnl_lookup()msrc · 2026-06-09
External references
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[](https://www.csirts.com/cve/CVE-2026-53221)