Patch Forecast
Amber warning
Patch this week.

CVE-2026-83856

Microsoft Windows 11 23h2: out-of-bounds read

Risk score
73/100
CVSS
8.1 v3.1
Exploit chance (30 days)
0.6%
Published
13 Oct 2026

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What to know

What it is
Out-of-bounds read in Windows Event Logging Service allows an unauthorized attacker to execute code over a network.
Affected
Microsoft Windows 11 23h2
Fix
Apply the vendor's security update; see the linked advisory.
Exploitation
No known exploitation

Story map

Story map: Microsoft Windows 11 23h2THE FLAWSTHE FIXCVE-2026-83856Out-of-bounds readCVSS 8.1 · EPSS 1%CVE-2026-100219Use-after-freeCVSS 9.8 · EPSS 1%CVE-2026-96909Heap buffer overflowCVSS 9.8 · EPSS 1%CVE-2026-85818Improper verification ofcryptographic signature inWindows Schannel allows an…CVSS 9.0 · EPSS 0%FixApply the vendor's securityupdate; see the linked advisory.Who is exposedMicrosoft Windows 11 23h2RED · ACT TODAYMicrosoftWindows 11 23h2Use after free in MicrosoftQUIC allows an unauthorizedattacker to execute code over anetwork.Where it standsNo known exploitationCONNECTS TOSame weaknessOut-of-bounds read (CWE-125)348 other warnings in 30 days →Same productEarlier Microsoft Windows 11 23h2 warnings31 in the last 90 days →
Story map: the flaws, the fix, how it unfolded and what it connects to. Boxes link to the record or article.

At a glance

Microsoft Windows 11 23h2: Red, act today. Use after free in Microsoft QUIC allows an unauthorized attacker to execute code over a network.

The flaws

  • CVE-2026-83856: Out-of-bounds read (CVSS 8.1 · EPSS 1%)
  • CVE-2026-100219: Use-after-free (CVSS 9.8 · EPSS 1%)
  • CVE-2026-96909: Heap buffer overflow (CVSS 9.8 · EPSS 1%)
  • CVE-2026-85818: Improper verification of cryptographic signature in Windows Schannel allows an unauthorized… (CVSS 9.0 · EPSS 0%)

The fix

Fix: Apply the vendor's security update; see the linked advisory.

Who is exposed: Microsoft Windows 11 23h2

Where it stands

  • No known exploitation

Connects to

Why it is Amber

  • CVSS 8.1 high
  • Remotely exploitable without logging in
  • On your watchlist: windows server

References

Original description

Out-of-bounds read in Windows Event Logging Service allows an unauthorized attacker to execute code over a network.

Last activity 13 Oct 2026. Patch Forecast updates every hour.