CVE-2026-85790ImportantFix has a known issueInformation DisclosureNetworkRevised 16 Oct

Microsoft QUIC Information Disclosure Vulnerability

MSRC advisory NVD CVE.org

Assessment

Use after free in Microsoft QUIC allows an unauthorized attacker to disclose information over a network.

Severity: Important
CVSS base score: 5.9CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C
Impact: Information Disclosure
EPSS, next 30 days: 0.8%Higher than 56.4% of scored CVEs · FIRST model run 25 Oct 2026 · about EPSS
Public exploit code: No Nuclei template lists it
Exploitability: Exploitation Less Likely
Publicly disclosed: No
Customer action: Required: apply the update
Component: Microsoft QUIC
Weakness: CWE-416: Use After Free
Issued by: Microsoft
Published: 13 Oct 2026 · October 2026
Last revised: 16 Oct 2026Updated the Security Updates table to add download and KB article links for Microsoft Visual Studio. This is an informational change only; the fixed builds are unchanged.

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: HighAC:H
Privileges required: NonePR:N
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: HighC:H
Integrity: NoneI:N
Availability: NoneA:N

Updates that fix it

5 KBs

KB	Type	Restart	Applies to	Known issues	Other CVEs
KB5126646	Security Update	Required	Windows Server 2025, Windows Server 2025 (Server Core installation)	MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server	All CVEs in KB5126646
KB5126653	Security Update	Required	Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems	None listed	All CVEs in KB5126653
KB5126655	Security Update	Required	Windows Server 2022, Windows Server 2022 (Server Core installation)	MitigatedUsers might be unable to sign in to OWA or send emails on Exchange Server	All CVEs in KB5126655
KB5127646	Security Update	Required	Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems	None listed	All CVEs in KB5127646
KB5127648	Security Update	Required	Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems and 3 more	None listed	All CVEs in KB5127648

Affected products

Developer Tools, Other, Windows

20 affected products

Microsoft Visual Studio 2022 version 17.14
Microsoft Visual Studio 2026 version 18.10
Microsoft.Native.Quic.MsQuic.Schannel on .NET 10.0 runtime installed on Windows
Microsoft.Native.Quic.MsQuic.Schannel on .NET 11.0 runtime installed on Windows
Microsoft.Native.Quic.MsQuic.Schannel on .NET 8.0 runtime installed on Windows
Microsoft.Native.Quic.MsQuic.Schannel on .NET 9.0 runtime installed on Windows
Windows 11 Version 23H2 for ARM64-based Systems
Windows 11 Version 23H2 for x64-based Systems
Windows 11 Version 24H2 for ARM64-based Systems
Windows 11 Version 24H2 for x64-based Systems
Windows 11 Version 25H2 for ARM64-based Systems
Windows 11 Version 25H2 for x64-based Systems
Windows 11 Version 26H1 for ARM64-based Systems
Windows 11 version 26H1 for x64-based Systems
Windows 11 Version 26H2 for ARM64-based Systems
Windows 11 Version 26H2 for x64-based Systems
Windows Server 2022
Windows Server 2022 (Server Core installation)
Windows Server 2025
Windows Server 2025 (Server Core installation)

What changed

First observed 14 Oct 2026

25 Oct 2026 · 17:12:51 UTC EPSS0.7%; scored 24 Oct 2026 → 0.8%; scored 25 Oct 2026
25 Oct 2026 · 01:34:18 UTC EPSS0.7%; scored 23 Oct 2026 → 0.7%; scored 24 Oct 2026
23 Oct 2026 · 15:51:28 UTC EPSS0.7%; scored 22 Oct 2026 → 0.7%; scored 23 Oct 2026
23 Oct 2026 · 09:33:49 UTC Public exploit codeUnknown: exploit-code evidence is incomplete or retained → No Nuclei template listed
23 Oct 2026 · 09:33:49 UTC CISA KEVUnknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
23 Oct 2026 · 09:33:49 UTC Source coverage: public-exploit-codeIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: first-epssIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: cisa-kevIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: msrc-cvrfIncomplete → Current
23 Oct 2026 · 08:31:50 UTC Public exploit codeNo Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC CISA KEVNot listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC Source coverage: public-exploit-codeCurrent → Incomplete

Show 17 more recent changes

23 Oct 2026 · 08:31:50 UTCSource coverage: first-epss Current → Incomplete
23 Oct 2026 · 08:31:50 UTCSource coverage: cisa-kev Current → Incomplete
23 Oct 2026 · 08:31:50 UTCSource coverage: msrc-cvrf Current → Incomplete
22 Oct 2026 · 22:02:57 UTCAffected products Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft.Native.Quic.MsQuic.Schannel on .NET 10.0 installed on Windows, Microsoft.Native.Quic.MsQuic.Schannel on .NET 11.0 installed on Windows, Microsoft.Native.Quic.MsQuic.Schannel on .NET 8.0 installed on Windows, Microsoft.Native.Quic.MsQuic.Schannel on .NET 9.0 installed on Windows, Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems, Windows 11 Version 26H2 for ARM64-based Systems, Windows 11 Version 26H2 for x64-based Systems, Windows Server 2022, Windows Server 2022 (Server Core installation), Windows Server 2025, Windows Server 2025 (Server Core installation) → Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft.Native.Quic.MsQuic.Schannel on .NET 10.0 runtime installed on Windows, Microsoft.Native.Quic.MsQuic.Schannel on .NET 11.0 runtime installed on Windows, Microsoft.Native.Quic.MsQuic.Schannel on .NET 8.0 runtime installed on Windows, Microsoft.Native.Quic.MsQuic.Schannel on .NET 9.0 runtime installed on Windows, Windows 11 Version 23H2 for ARM64-based Systems, Windows 11 Version 23H2 for x64-based Systems, Windows 11 Version 24H2 for ARM64-based Systems, Windows 11 Version 24H2 for x64-based Systems, Windows 11 Version 25H2 for ARM64-based Systems, Windows 11 Version 25H2 for x64-based Systems, Windows 11 Version 26H1 for ARM64-based Systems, Windows 11 version 26H1 for x64-based Systems, Windows 11 Version 26H2 for ARM64-based Systems, Windows 11 Version 26H2 for x64-based Systems, Windows Server 2022, Windows Server 2022 (Server Core installation), Windows Server 2025, Windows Server 2025 (Server Core installation)
22 Oct 2026 · 17:33:15 UTCEPSS 0.7%; scored 21 Oct 2026 → 0.7%; scored 22 Oct 2026
21 Oct 2026 · 21:47:24 UTCEPSS 0.7%; scored 20 Oct 2026 → 0.7%; scored 21 Oct 2026
20 Oct 2026 · 20:53:31 UTCEPSS 0.7%; scored 19 Oct 2026 → 0.7%; scored 20 Oct 2026
19 Oct 2026 · 15:12:40 UTCEPSS 0.7%; scored 18 Oct 2026 → 0.7%; scored 19 Oct 2026
18 Oct 2026 · 14:54:30 UTCEPSS 0.7%; scored 16 Oct 2026 → 0.7%; scored 18 Oct 2026
18 Oct 2026 · 14:54:30 UTCLink: October 2026 → /security?release=2026-Oct#cves
17 Oct 2026 · 07:28:24 UTCRevision note Updated the Security Updates table to add KB article links for .NET 11.0. This is an informational change only; the fixed builds are unchanged. → Updated the Security Updates table to add download and KB article links for Microsoft Visual Studio. This is an informational change only; the fixed builds are unchanged.
17 Oct 2026 · 07:28:24 UTCLast revised 15 Oct 2026 07:00 UTC → 16 Oct 2026 07:00 UTC
16 Oct 2026 · 16:13:25 UTCEPSS 0.7%; scored 15 Oct 2026 → 0.7%; scored 16 Oct 2026
15 Oct 2026 · 21:30:54 UTCRevision note Information published. → Updated the Security Updates table to add KB article links for .NET 11.0. This is an informational change only; the fixed builds are unchanged.
15 Oct 2026 · 21:30:54 UTCLast revised 13 Oct 2026 07:00 UTC → 15 Oct 2026 07:00 UTC
15 Oct 2026 · 21:30:54 UTCEPSS 0.7%; scored 14 Oct 2026 → 0.7%; scored 15 Oct 2026
15 Oct 2026 · 01:07:54 UTCEPSS Not scored → 0.7%; scored 14 Oct 2026

The most recent 100 field changes are listed. Complete recorded revisions are kept separately.

Cite this recorded revision to keep the same title, summary, facts and links when the page changes.

A day selects the latest observation by the end of that UTC day; today's selection can change until midnight. History starts when this installation records it.

Explore global source statements, affected packages and advisory history for CVE-2026-85790. The catalog has a separate collection scope from Microsoft release records.

Collected exploitation and prediction evidence

Risk source coverage

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

CVE-2026-85790

No KEV entry is attached to this observation; this is not evidence that exploitation is absent.

FIRST EPSS: 0.80 % · percentile 56.45 % · scored 25 Oct 2026.

Observed 25 Oct 2026 15:18:41 UTC · Complete immutable risk JSON

Dated risk observations

Risk history is separate from CNA/OSV content history. Daily score drift is retained but only an upward crossing of 10% triggers the prediction change event.

CVE-2026-85790 · 25 Oct 2026 15:18:41 UTC

CVE-2026-85790 · 25 Oct 2026 02:24:38 UTC

CVE-2026-85790 · 23 Oct 2026 16:01:26 UTC

Immutable source observations

6 recorded revisions

Each citation identifies one complete source statement. Source modification dates and the time this installation observed them are distinct. Latest history includes records historically associated by source identifiers; a removed alias is not a current equivalence claim. Exact citations show that source record's own earlier observations. Failed reads and unchanged polls do not rewrite history.

25 Oct 2026 19:02:14 UTC