CVE-2026-87697ImportantRCENetworkRevised 15 Oct

.NET Remote Code Execution Vulnerability

MSRC advisory NVD CVE.org

Assessment

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

Severity: Important
CVSS base score: 8.8CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
Impact: Remote Code Execution
EPSS, next 30 days: 0.8%Higher than 57.7% 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: .NET
Weakness: CWE-502: Deserialization of Untrusted Data
Issued by: Microsoft
Published: 13 Oct 2026 · October 2026
Last revised: 15 Oct 2026Updated the Security Updates table to add KB article links for .NET 11.0 and 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: LowAC:L
Privileges required: NonePR:N
User interaction: RequiredUI:R
Scope: UnchangedS:U
Confidentiality: HighC:H
Integrity: HighI:H
Availability: HighA:H

Updates that fix it

3 KBs

KB	Type	Restart	Applies to	Other CVEs
KB5130034	Security Update	Required	.NET 8.0 runtime installed on Windows	All CVEs in KB5130034
KB5130035	Security Update	Required	.NET 9.0 runtime installed on Windows	All CVEs in KB5130035
KB5130036	Security Update	Required	.NET 10.0 runtime installed on Windows	All CVEs in KB5130036

Affected products

Developer Tools

6 affected products

.NET 10.0 runtime installed on Windows
.NET 11.0 runtime installed on Windows
.NET 8.0 runtime installed on Windows
.NET 9.0 runtime installed on Windows
Microsoft Visual Studio 2022 version 17.14
Microsoft Visual Studio 2026 version 18.10

What changed

First observed 14 Oct 2026

25 Oct 2026 · 17:12:51 UTC EPSS0.8%; scored 24 Oct 2026 → 0.8%; scored 25 Oct 2026
25 Oct 2026 · 01:34:18 UTC EPSS0.8%; scored 23 Oct 2026 → 0.8%; scored 24 Oct 2026
23 Oct 2026 · 15:51:28 UTC EPSS0.8%; scored 22 Oct 2026 → 0.8%; 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 20 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 UTCUpdates that fix it KB5130034: .NET 8.0 installed on Windows (restart required); KB5130035: .NET 9.0 installed on Windows (restart required); KB5130036: .NET 10.0 installed on Windows (restart required) → KB5130034: .NET 8.0 runtime installed on Windows (restart required); KB5130035: .NET 9.0 runtime installed on Windows (restart required); KB5130036: .NET 10.0 runtime installed on Windows (restart required)
22 Oct 2026 · 22:02:57 UTCAffected products .NET 10.0 installed on Windows, .NET 11.0 installed on Windows, .NET 8.0 installed on Windows, .NET 9.0 installed on Windows, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10 → .NET 10.0 runtime installed on Windows, .NET 11.0 runtime installed on Windows, .NET 8.0 runtime installed on Windows, .NET 9.0 runtime installed on Windows, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10
22 Oct 2026 · 17:33:15 UTCEPSS 0.8%; scored 21 Oct 2026 → 0.8%; scored 22 Oct 2026
21 Oct 2026 · 21:47:24 UTCEPSS 0.8%; scored 20 Oct 2026 → 0.8%; scored 21 Oct 2026
20 Oct 2026 · 20:53:31 UTCEPSS 0.8%; scored 19 Oct 2026 → 0.8%; scored 20 Oct 2026
19 Oct 2026 · 15:12:40 UTCEPSS 0.8%; scored 18 Oct 2026 → 0.8%; scored 19 Oct 2026
18 Oct 2026 · 14:54:30 UTCEPSS 0.8%; scored 16 Oct 2026 → 0.8%; scored 18 Oct 2026
18 Oct 2026 · 14:54:30 UTCLink: October 2026 → /security?release=2026-Oct#cves
16 Oct 2026 · 16:13:25 UTCEPSS 0.8%; scored 15 Oct 2026 → 0.8%; 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 and download and KB article links for Microsoft Visual Studio. 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 0.8%; scored 14 Oct 2026 → 0.8%; scored 15 Oct 2026
15 Oct 2026 · 21:30:54 UTCUpdates that fix it No KB listed → KB5130034: .NET 8.0 installed on Windows (restart required); KB5130035: .NET 9.0 installed on Windows (restart required); KB5130036: .NET 10.0 installed on Windows (restart required)
15 Oct 2026 · 21:30:54 UTCLink: KB5130036 → /windows/kb/KB5130036
15 Oct 2026 · 21:30:54 UTCLink: KB5130035 → /windows/kb/KB5130035
15 Oct 2026 · 21:30:54 UTCLink: KB5130034 → /windows/kb/KB5130034
15 Oct 2026 · 01:07:54 UTCEPSS Not scored → 0.8%; scored 14 Oct 2026

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

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Explore global source statements, affected packages and advisory history for CVE-2026-87697. 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-2026-87697

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

FIRST EPSS: 0.84 % · percentile 57.68 % · scored 25 Oct 2026.

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

cve-program · CVE-2026-87697

Published

.NET Remote Code Execution Vulnerability

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

Source published: 13 Oct 2026 19:00:16 UTC
Source modified: 25 Oct 2026 18:42:22 UTC
Observed here: 25 Oct 2026 20:02:02 UTC
Source terms: CVE Program Terms of Use

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: cve-program · CVE Program Terms of Use. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

nvd · CVE-2026-87697

Published

Deserialization of untrusted data in .NET allows an unauthorized attacker to execute code over a network.

NVD analysis and CPE criteria are source context, not proof that a package or your environment is affected. Complete affected data, logical configurations and SSVC are retained in the original JSON.

Source analysis status: Undergoing Analysis

Weakness classifications: CWE-502

Original publisher date fields

published: 2026-10-13T19:21:22.400

lastModified: 2026-10-22T22:19:39.090

Source published: 13 Oct 2026 19:21:22 UTC
Source modified: 22 Oct 2026 22:19:39 UTC
Observed here: 25 Oct 2026 16:19:22 UTC
Source terms: NIST NVD usage terms; underlying source attribution retained

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 3.1 · [email protected] · Secondary · 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

osv · GHSA-c27m-942f-rcfh

Published

Microsoft Security Advisory CVE-2026-87697 - .NET and Visual Studio Remote Code Execution Vulnerability

## Executive summary Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.WindowsDesktop.App.Runtime (WPF). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability. WPF XPS synthetic hyperlinks exposed through UI Automation can bypass restrictive navigation checks and reach attacker-controlled content, enabling remote code execution after user interaction. ## Announcement Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/471 ## CVSS Details - **Version:** 3.1 - **Severity:** High - **Score:** 8.8 - **Vector:** `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H` - **Weakness:** CWE-502 (Deserialization of Untrusted Data) ## Affected Platforms - **Platforms:** Windows - **Architectures:** All ## <a name="affected-packages"></a>Affected Packages The vulnerability affects Microsoft .NET projects that use an affected package version listed below. Package name | Affected version | Patched version ------------ | ---------------- | --------------- [Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64) | >= 9.0.0, <= 9.0.20 | 9.0.21 [Microsoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64) | >= 9.0.0, <= 9.0.20 | 9.0.21 [Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86) | >= 9.0.0, <= 9.0.20 | 9.0.21 [Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64) | >= 8.0.0, <= 8.0.31 | 8.0.32 [Microsoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64) | >= 8.0.0, <= 8.0.31 | 8.0.32 [Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86) | >= 8.0.0, <= 8.0.31 | 8.0.32 [Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64) | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 [Microsoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64) | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 [Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86) | >= 11.0.0-preview.1, <= 11.0.0-rc.1 | 11.0.0-rc.2 [Microsoft.WindowsDesktop.App.Runtime.win-arm64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-arm64) | >= 10.0.0, <= 10.0.12 | 10.0.13 [Microsoft.WindowsDesktop.App.Runtime.win-x64](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x64) | >= 10.0.0, <= 10.0.12 | 10.0.13 [Microsoft.WindowsDesktop.App.Runtime.win-x86](https://www.nuget.org/packages/Microsoft.WindowsDesktop.App.Runtime.win-x86) | >= 10.0.0, <= 10.0.12 | 10.0.13 ## Advisory FAQ ### <a name="how-affected"></a>How do I know if I am affected? If using a package listed in [affected packages](#affected-packages), you're exposed to the vulnerability. ### <a name="how-fix"></a>How do I fix the issue? 1. To fix the issue please install the latest version of .NET. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs. 2. If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the `dotnet --info` command. Once you have installed the updated runtime or SDK, restart your apps for the update to take effect. Additionally, if you've deployed [self-contained applications](https://docs.microsoft.com/dotnet/core/deploying/#self-contained-deployments-scd) targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed. ## Other Information ### Reporting Security Issues If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the [MSRC Researcher Portal](https://msrc.microsoft.com/report/vulnerability/new). Further information can be found in the MSRC [Report an Issue FAQ](https://www.microsoft.com/msrc/faqs-report-an-issue). Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty. ### Support You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue. ### Disclaimer The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply. ### External Links [CVE-2026-87697](https://www.cve.org/CVERecord?id=CVE-2026-87697) ### Acknowledgements - 41ae55e9310ff27fa6f26af4727e5590 ### Revisions V1.0 (10/13/2026): Advisory published.

Source published: 13 Oct 2026 20:52:24 UTC
Source modified: 19 Oct 2026 19:30:12 UTC
Observed here: 23 Oct 2026 16:01:25 UTC
Source terms: GitHub Advisory Database · CC-BY-4.0

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Publisher rating · HIGH