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Fencer Vulns
high 8.8

CVE-2026-87697 json

.NET Remote Code Execution Vulnerability

published 2026-10-13 26 d ago modified 2026-10-31 8 d ago also GHSA-c27m-942f-rcfh , EUVD-2026-99638

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.8%
EPSS 0.8% chance of exploitation in 30 days, percentile 58%
public exploits
0
none known

Summary

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

Patch / fix

  • nuget Microsoft.WindowsDesktop.App.Runtime.win-arm64 8.0.32, 9.0.21, 10.0.13, 11.0.0-rc.2
  • nuget Microsoft.WindowsDesktop.App.Runtime.win-x64 8.0.32, 9.0.21, 10.0.13, 11.0.0-rc.2
  • nuget Microsoft.WindowsDesktop.App.Runtime.win-x86 8.0.32, 9.0.21, 10.0.13, 11.0.0-rc.2
  • Microsoft .NET 10.0 runtime 10.0.13
  • Microsoft .NET 11.0 runtime 11.0.0-rc.2
  • Microsoft .NET 8.0 runtime 8.0.32
  • Microsoft .NET 9.0 runtime 9.0.21
  • Microsoft Microsoft Visual Studio 2022 version 17.14 17.14.42
  • Microsoft Microsoft Visual Studio 2026 version 18.10 18.10.4
  • dotnet8.0 hummingbird 1 8.0.132-0.1.hum1
  • dotnet-sdk-8.0 hummingbird 1 8.0.132-0.1.hum1
  • dotnet-hostfxr-8.0 hummingbird 1 8.0.32-0.1.hum1
  • dotnet-runtime-8.0 hummingbird 1 8.0.32-0.1.hum1
  • dotnet-sdk-dbg-8.0 hummingbird 1 8.0.132-0.1.hum1
  • dotnet-templates-8.0 hummingbird 1 8.0.132-0.1.hum1
  • aspnetcore-runtime-8.0 hummingbird 1 8.0.32-0.1.hum1
  • dotnet-runtime-dbg-8.0 hummingbird 1 8.0.32-0.1.hum1

red hat advisories RHSA-2026:84693

  • dotnet8-runtime Alpine 3.24, Alpine 3.23, Alpine 3.22 8.0.32-r0
  • dotnet9-runtime Alpine 3.24, Alpine 3.23, Alpine 3.22 9.0.21-r0
  • dotnet10-runtime Alpine 3.24, Alpine 3.23 10.0.13-r0

alpine advisories ALPINE-CVE-2026-87697

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-87697 updated

dotnet: dotnet: arbitrary code execution via untrusted data deserialization

  • Red Hat Hardened Images dotnet8.0 8.0.132-0.1.hum1, dotnet-sdk-8.0 8.0.132-0.1.hum1, dotnet-sdk-dbg-8.0 8.0.132-0.1.hum1, dotnet-templates-8.0 8.0.132-0.1.hum1, dotnet-sdk-8.0-source-built-artifacts 8.0.132-0.1.hum1
    fixed: vendor fix RHSA-2026:84693
  • Red Hat Hardened Images dotnet-hostfxr-8.0 8.0.32-0.1.hum1, dotnet-runtime-8.0 8.0.32-0.1.hum1, aspnetcore-runtime-8.0 8.0.32-0.1.hum1, dotnet-runtime-dbg-8.0 8.0.32-0.1.hum1, dotnet-apphost-pack-8.0 8.0.32-0.1.hum1, dotnet-targeting-pack-8.0 8.0.32-0.1.hum1, +2 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
total
Assessed
32 d ago

Exploit prediction

0.84% chance of exploitation in the next 30 days, higher than 58% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 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
CNA 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
GitHub 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
nuget Microsoft.WindowsDesktop.App.Runtime.win-arm64
>=9.0.0, <9.0.21
>=8.0.0, <8.0.32
>=11.0.0-preview.1, <11.0.0-rc.2
>=10.0.0, <10.0.13
9.0.21
8.0.32
11.0.0-rc.2
10.0.13
nuget Microsoft.WindowsDesktop.App.Runtime.win-x64
>=9.0.0, <9.0.21
>=8.0.0, <8.0.32
>=11.0.0-preview.1, <11.0.0-rc.2
>=10.0.0, <10.0.13
9.0.21
8.0.32
11.0.0-rc.2
10.0.13
nuget Microsoft.WindowsDesktop.App.Runtime.win-x86
>=9.0.0, <9.0.21
>=8.0.0, <8.0.32
>=11.0.0-preview.1, <11.0.0-rc.2
>=10.0.0, <10.0.13
9.0.21
8.0.32
11.0.0-rc.2
10.0.13

Affected products

  • Microsoft .NET 10.0 runtime
  • Microsoft .NET 11.0 runtime
  • Microsoft .NET 8.0 runtime
  • Microsoft .NET 9.0 runtime
  • Microsoft Microsoft Visual Studio 2022 version 17.14
  • Microsoft Microsoft Visual Studio 2026 version 18.10

Classification

Weakness
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.