Security October 2026 CVE-2026-87697
AssessmentDeserialization 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
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 metrics Red 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
Affected productsDeveloper Tools
Source. This summary comes from MSRC's public CVRF document for October 2026. If the MSRC page is blocked in your browser, the NVD and CVE.org records carry the same identifier. None of this says whether your devices are affected.
What changedFirst observed 14 Oct 2026 25 Oct 2026 · 17:12:51 UTC
EPSS 0.8%; scored 24 Oct 2026 → 0.8%; scored 25 Oct 2026 25 Oct 2026 · 01:34:18 UTC
EPSS 0.8%; scored 23 Oct 2026 → 0.8%; scored 24 Oct 2026 23 Oct 2026 · 15:51:28 UTC
EPSS 0.8%; scored 22 Oct 2026 → 0.8%; scored 23 Oct 2026 23 Oct 2026 · 09:33:49 UTC
Public exploit code Unknown: exploit-code evidence is incomplete or retained → No Nuclei template listed 23 Oct 2026 · 09:33:49 UTC
CISA KEV Unknown: catalog evidence is incomplete or retained → Not listed in the collected catalog 23 Oct 2026 · 09:33:49 UTC
Source coverage: public-exploit-code Incomplete → Current 23 Oct 2026 · 09:33:49 UTC
Source coverage: first-epss Incomplete → Current 23 Oct 2026 · 09:33:49 UTC
Source coverage: cisa-kev Incomplete → Current 23 Oct 2026 · 09:33:49 UTC
Source coverage: msrc-cvrf Incomplete → Current 23 Oct 2026 · 08:31:50 UTC
Public exploit code No Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained 23 Oct 2026 · 08:31:50 UTC
CISA KEV Not listed in the collected catalog → Unknown: catalog evidence is incomplete or retained 23 Oct 2026 · 08:31:50 UTC
Source coverage: public-exploit-code Current → Incomplete Show 20 more recent changes 23 Oct 2026 · 08:31:50 UTC Source coverage: first-epss Current → Incomplete23 Oct 2026 · 08:31:50 UTC Source coverage: cisa-kev Current → Incomplete23 Oct 2026 · 08:31:50 UTC Source coverage: msrc-cvrf Current → Incomplete22 Oct 2026 · 22:02:57 UTC Updates 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 UTC Affected 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 18.1022 Oct 2026 · 17:33:15 UTC EPSS 0.8%; scored 21 Oct 2026 → 0.8%; scored 22 Oct 202621 Oct 2026 · 21:47:24 UTC EPSS 0.8%; scored 20 Oct 2026 → 0.8%; scored 21 Oct 202620 Oct 2026 · 20:53:31 UTC EPSS 0.8%; scored 19 Oct 2026 → 0.8%; scored 20 Oct 202619 Oct 2026 · 15:12:40 UTC EPSS 0.8%; scored 18 Oct 2026 → 0.8%; scored 19 Oct 202618 Oct 2026 · 14:54:30 UTC EPSS 0.8%; scored 16 Oct 2026 → 0.8%; scored 18 Oct 202618 Oct 2026 · 14:54:30 UTC Link: October 2026 → /security?release=2026-Oct#cves16 Oct 2026 · 16:13:25 UTC EPSS 0.8%; scored 15 Oct 2026 → 0.8%; scored 16 Oct 202615 Oct 2026 · 21:30:54 UTC Revision 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 UTC Last revised 13 Oct 2026 07:00 UTC → 15 Oct 2026 07:00 UTC15 Oct 2026 · 21:30:54 UTC EPSS 0.8%; scored 14 Oct 2026 → 0.8%; scored 15 Oct 202615 Oct 2026 · 21:30:54 UTC Updates 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 UTC Link: KB5130036 → /windows/kb/KB513003615 Oct 2026 · 21:30:54 UTC Link: KB5130035 → /windows/kb/KB513003515 Oct 2026 · 21:30:54 UTC Link: KB5130034 → /windows/kb/KB513003415 Oct 2026 · 01:07:54 UTC EPSS Not scored → 0.8%; scored 14 Oct 2026The 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.
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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.
Overview Affected History Connections
cve-program · CVE-2026-87697 Published .NET 10.0 runtime Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": ".NET 10.0 runtime",
"versions": [
{
"version": "10.0.0",
"lessThan": "10.0.13",
"versionType": "custom",
"status": "affected"
}
]
} .NET 11.0 runtime Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": ".NET 11.0 runtime",
"versions": [
{
"version": "11.0.0",
"lessThan": "11.0.0-rc.2",
"versionType": "custom",
"status": "affected"
}
]
} .NET 8.0 runtime Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": ".NET 8.0 runtime",
"versions": [
{
"version": "8.0.0",
"lessThan": "8.0.32",
"versionType": "custom",
"status": "affected"
}
]
} .NET 9.0 runtime Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": ".NET 9.0 runtime",
"versions": [
{
"version": "9.0.0",
"lessThan": "9.0.21",
"versionType": "custom",
"status": "affected"
}
]
} Microsoft Visual Studio 2022 version 17.14 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Microsoft Visual Studio 2022 version 17.14",
"versions": [
{
"version": "17.14.0",
"lessThan": "17.14.42",
"versionType": "custom",
"status": "affected"
}
]
} Microsoft Visual Studio 2026 version 18.10 Vendor product
Original vendor version evidence · not evaluated as a NuGet range {
"vendor": "Microsoft",
"product": "Microsoft Visual Studio 2026 version 18.10",
"versions": [
{
"version": "18.10.0",
"lessThan": "18.10.4",
"versionType": "custom",
"status": "affected"
}
]
}
nvd · CVE-2026-87697 Published No affected-package array is stated in this source revision. Check its state and earlier observations; this does not establish that every package is unaffected.
osv · GHSA-c27m-942f-rcfh Published Microsoft.WindowsDesktop.App.Runtime.win-arm64 NuGet
ECOSYSTEM · introduced 9.0.0 → fixed 9.0.21
21 explicitly affected versions 9.0.0, 9.0.1, 9.0.10, 9.0.11, 9.0.12, 9.0.13, 9.0.14, 9.0.15, 9.0.16, 9.0.17, 9.0.18, 9.0.19, 9.0.2, 9.0.20, 9.0.3, 9.0.4, 9.0.5, 9.0.6, 9.0.7, 9.0.8, 9.0.9
Microsoft.WindowsDesktop.App.Runtime.win-x64 NuGet
ECOSYSTEM · introduced 9.0.0 → fixed 9.0.21
21 explicitly affected versions 9.0.0, 9.0.1, 9.0.10, 9.0.11, 9.0.12, 9.0.13, 9.0.14, 9.0.15, 9.0.16, 9.0.17, 9.0.18, 9.0.19, 9.0.2, 9.0.20, 9.0.3, 9.0.4, 9.0.5, 9.0.6, 9.0.7, 9.0.8, 9.0.9
Microsoft.WindowsDesktop.App.Runtime.win-x86 NuGet
ECOSYSTEM · introduced 9.0.0 → fixed 9.0.21
21 explicitly affected versions 9.0.0, 9.0.1, 9.0.10, 9.0.11, 9.0.12, 9.0.13, 9.0.14, 9.0.15, 9.0.16, 9.0.17, 9.0.18, 9.0.19, 9.0.2, 9.0.20, 9.0.3, 9.0.4, 9.0.5, 9.0.6, 9.0.7, 9.0.8, 9.0.9
Microsoft.WindowsDesktop.App.Runtime.win-arm64 NuGet
ECOSYSTEM · introduced 8.0.0 → fixed 8.0.32
31 explicitly affected versions 8.0.0, 8.0.1, 8.0.10, 8.0.11, 8.0.12, 8.0.13, 8.0.14, 8.0.15, 8.0.16, 8.0.17, 8.0.18, 8.0.19, 8.0.2, 8.0.20, 8.0.21, 8.0.22, 8.0.23, 8.0.24, 8.0.25, 8.0.26, 8.0.27, 8.0.28, 8.0.29, 8.0.3, 8.0.30, 8.0.31, 8.0.4, 8.0.5, 8.0.6, 8.0.7, 8.0.8
Microsoft.WindowsDesktop.App.Runtime.win-x64 NuGet
ECOSYSTEM · introduced 8.0.0 → fixed 8.0.32
31 explicitly affected versions 8.0.0, 8.0.1, 8.0.10, 8.0.11, 8.0.12, 8.0.13, 8.0.14, 8.0.15, 8.0.16, 8.0.17, 8.0.18, 8.0.19, 8.0.2, 8.0.20, 8.0.21, 8.0.22, 8.0.23, 8.0.24, 8.0.25, 8.0.26, 8.0.27, 8.0.28, 8.0.29, 8.0.3, 8.0.30, 8.0.31, 8.0.4, 8.0.5, 8.0.6, 8.0.7, 8.0.8
Microsoft.WindowsDesktop.App.Runtime.win-x86 NuGet
ECOSYSTEM · introduced 8.0.0 → fixed 8.0.32
31 explicitly affected versions 8.0.0, 8.0.1, 8.0.10, 8.0.11, 8.0.12, 8.0.13, 8.0.14, 8.0.15, 8.0.16, 8.0.17, 8.0.18, 8.0.19, 8.0.2, 8.0.20, 8.0.21, 8.0.22, 8.0.23, 8.0.24, 8.0.25, 8.0.26, 8.0.27, 8.0.28, 8.0.29, 8.0.3, 8.0.30, 8.0.31, 8.0.4, 8.0.5, 8.0.6, 8.0.7, 8.0.8
Microsoft.WindowsDesktop.App.Runtime.win-arm64 NuGet
ECOSYSTEM · introduced 11.0.0-preview.1 → fixed 11.0.0-rc.2
Microsoft.WindowsDesktop.App.Runtime.win-x64 NuGet
ECOSYSTEM · introduced 11.0.0-preview.1 → fixed 11.0.0-rc.2
Microsoft.WindowsDesktop.App.Runtime.win-x86 NuGet
ECOSYSTEM · introduced 11.0.0-preview.1 → fixed 11.0.0-rc.2
Microsoft.WindowsDesktop.App.Runtime.win-arm64 NuGet
ECOSYSTEM · introduced 10.0.0 → fixed 10.0.13
13 explicitly affected versions 10.0.0, 10.0.1, 10.0.10, 10.0.11, 10.0.12, 10.0.2, 10.0.3, 10.0.4, 10.0.5, 10.0.6, 10.0.7, 10.0.8, 10.0.9
Microsoft.WindowsDesktop.App.Runtime.win-x64 NuGet
ECOSYSTEM · introduced 10.0.0 → fixed 10.0.13
13 explicitly affected versions 10.0.0, 10.0.1, 10.0.10, 10.0.11, 10.0.12, 10.0.2, 10.0.3, 10.0.4, 10.0.5, 10.0.6, 10.0.7, 10.0.8, 10.0.9
Microsoft.WindowsDesktop.App.Runtime.win-x86 NuGet
ECOSYSTEM · introduced 10.0.0 → fixed 10.0.13
13 explicitly affected versions 10.0.0, 10.0.1, 10.0.10, 10.0.11, 10.0.12, 10.0.2, 10.0.3, 10.0.4, 10.0.5, 10.0.6, 10.0.7, 10.0.8, 10.0.9