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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-62815

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

CRITICAL 9.8EPSS 0.97%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.97%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

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

CVSS 3.1
9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.97% probability · 62th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-416
Affected
microsoft/windows 11 23h2 · microsoft/windows 11 24h2 · microsoft/windows 11 25h2 · microsoft/windows 11 26h1 · microsoft/windows server 2022 · microsoft/windows server 2025
Source
secure@microsoft.com
EPSS trend
0%3%5%26 October 2026: 0.97%26 October 202626 October 2026

EPSS 1.0% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.