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CVE-2026-100219

CRITICAL 9.8

Published 2026-10-13 · Last modified 2026-10-19

Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

1.0%chance of exploitation in 30 days · 62nd percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

9.8CVSS 3.1 · CRITICAL

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-100219/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-100219/poc.json

Affected

Vendors Microsoft

Products Windows 11 Version 23h2 Windows 11 Version 24h2 Windows 11 Version 25h2 Windows 11 Version 26h1 Windows 11 Version 26h2 Windows Server 2022 Windows Server 2025 Windows Server 2025 (Server Core Installation)

Weakness (CWE)

  • CWE-416: : Use After Free

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

All CVSS metrics

  • CRITICAL 9.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

Patches & mitigations

Sources: NVD · CVE.org · EPSS