CVE-2026-102870ImportantRCENetworkRevised 25 Oct

ASP.NET Core Remote Code Execution Vulnerability

MSRC advisory NVD CVE.org

Assessment

Improper control of generation of code ('code injection') in ASP.NET Core 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: 0.9%Higher than 59.6% 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: ASP.NET Core
Weakness: CWE-94: Improper Control of Generation of Code ('Code Injection')
Issued by: Microsoft
Published: 13 Oct 2026 · October 2026
Last revised: 25 Oct 2026Updated product information in the Software Update table. This is an informational change only.

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

1 KB

KB	Type	Restart	Applies to	Other CVEs
KB5133966	Security Update	Required	.NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows and 2 more	All CVEs in KB5133966

Affected products

Developer Tools, Other

19 affected products

.NET 10.0 installed on Linux
.NET 10.0 installed on Mac OS
.NET 10.0 installed on Windows
.NET 11.0 installed on Linux
.NET 11.0 installed on Mac OS
.NET 11.0 installed on Windows
Microsoft Visual Studio 2019 version 16.11
Microsoft Visual Studio 2022 version 17.14
Microsoft Visual Studio 2026 version 18.10
Microsoft Visual Studio 2026 version 18.11
Microsoft Visual Studio 2026 version 18.12
Microsoft.AspNetCore.Components.WebAssembly.DevServer
Microsoft.AspNetCore.Components.WebAssembly.Server
Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux
Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS
Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows
Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux
Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS
Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows

What changed

First observed 14 Oct 2026

25 Oct 2026 · 19:05:13 UTC Updates that fix itKB5133966: .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft.AspNetCore.Components.WebAssembly.Server (restart required) → KB5133966: .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.DevServer, Microsoft.AspNetCore.Components.WebAssembly.Server (restart required)
25 Oct 2026 · 19:05:13 UTC Affected products.NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, .NET 11.0 installed on Linux, .NET 11.0 installed on Mac OS, .NET 11.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft Visual Studio 2019 version 16.11, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft Visual Studio 2026 version 18.11, Microsoft Visual Studio 2026 version 18.12, Microsoft.AspNetCore.Components.WebAssembly.Server, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows → .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, .NET 11.0 installed on Linux, .NET 11.0 installed on Mac OS, .NET 11.0 installed on Windows, Microsoft Visual Studio 2019 version 16.11, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft Visual Studio 2026 version 18.11, Microsoft Visual Studio 2026 version 18.12, Microsoft.AspNetCore.Components.WebAssembly.DevServer, Microsoft.AspNetCore.Components.WebAssembly.Server, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows
25 Oct 2026 · 17:12:51 UTC Revision noteInformation published. → Updated product information in the Software Update table. This is an informational change only.
25 Oct 2026 · 17:12:51 UTC Last revised13 Oct 2026 07:00 UTC → 25 Oct 2026 07:00 UTC
25 Oct 2026 · 17:12:51 UTC EPSS0.8%; scored 24 Oct 2026 → 0.9%; scored 25 Oct 2026
25 Oct 2026 · 17:12:51 UTC Updates that fix itNo KB listed → KB5133966: .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft.AspNetCore.Components.WebAssembly.Server (restart required)
25 Oct 2026 · 17:12:51 UTC Affected productsMicrosoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows → .NET 10.0 installed on Linux, .NET 10.0 installed on Mac OS, .NET 10.0 installed on Windows, .NET 11.0 installed on Linux, .NET 11.0 installed on Mac OS, .NET 11.0 installed on Windows, Microsoft Edge (Chromium-based), Microsoft Visual Studio 2019 version 16.11, Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft Visual Studio 2026 version 18.11, Microsoft Visual Studio 2026 version 18.12, Microsoft.AspNetCore.Components.WebAssembly.Server, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows
25 Oct 2026 · 17:12:51 UTC Link: KB5133966/windows/kb/KB5133966
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

Show 20 more recent changes

23 Oct 2026 · 09:33:49 UTCSource coverage: public-exploit-code Incomplete → Current
23 Oct 2026 · 09:33:49 UTCSource coverage: first-epss Incomplete → Current
23 Oct 2026 · 09:33:49 UTCSource coverage: cisa-kev Incomplete → Current
23 Oct 2026 · 09:33:49 UTCSource coverage: msrc-cvrf Incomplete → Current
23 Oct 2026 · 08:31:50 UTCPublic exploit code No Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTCCISA KEV Not listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTCSource coverage: public-exploit-code Current → Incomplete
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.AspNetCore.Components.WebAssembly.Server on .NET 10.0 installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 installed on Windows → Microsoft Visual Studio 2022 version 17.14, Microsoft Visual Studio 2026 version 18.10, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 10.0 runtime installed on Windows, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Linux, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Mac OS, Microsoft.AspNetCore.Components.WebAssembly.Server on .NET 11.0 runtime installed on Windows
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 UTCEPSS 0.8%; scored 14 Oct 2026 → 0.8%; scored 15 Oct 2026
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.

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-2026-102870. 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-2026-102870

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

FIRST EPSS: 0.91 % · percentile 59.59 % · 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-2026-102870 · 25 Oct 2026 15:18:41 UTC

CVE-2026-102870 · 25 Oct 2026 02:24:38 UTC

CVE-2026-102870 · 23 Oct 2026 16:01:26 UTC

Immutable source observations

7 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 20:02:02 UTC