Out-of-Bounds Write in Microsoft.WindowsDesktop.App.Runtime.win-arm64 (CVE-2026-70007)
Summary
Out-of-bounds write in Microsoft.WindowsDesktop.App.Runtime.win-arm64 (CVE-2026-70007). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 8.0.32 or later.
Original description
The description as published by the source.
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.
Crafted WPF pixel-shader bytecode can desynchronize the two parsing passes in CPSTrans::Initialize, causing heap out-of-bounds writes or reads.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/450
CVSS Details
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Version: 3.1
-
Severity: High
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Score: 8.8
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Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H -
Weakness: CWE-787 (Out-of-bounds Write)
Affected Platforms
- Platforms: Windows
- Architectures: All
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 | >= 9.0.0, <= 9.0.20 | 9.0.21 |
| Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 9.0.0, <= 9.0.20 | 9.0.21 |
| Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 9.0.0, <= 9.0.20 | 9.0.21 |
| [Microso… |
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-70007 has been found in Microsoft.WindowsDesktop.App.Runtime.win-arm64.
Successful exploitation can lead to full system takeover. CVSS score: 8.8/10.
What to do: upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64 to 8.0.32 or later.
If unsure, ask your IT team or search "Microsoft.WindowsDesktop.App.Runtime.win-arm64 CVE-2026-70007" on the vendor's site.
CVE-2026-70007 (Microsoft.WindowsDesktop.App.Runtime.win-arm64) — CWE-787 / CVSS v3 8.8
Attack vector: remote (network-reachable) / unauthenticated
Patched: 8.0.32 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds write (CWE-787) exists in Microsoft.WindowsDesktop.App.Runtime.win-arm64.
Check the vendor advisory for the affected versions of Microsoft.WindowsDesktop.App.Runtime.win-arm64.
Severity: High (CVSS 8.8/10). Successful exploitation can lead to full system takeover.
Update to 8.0.32.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Microsoft.WindowsDesktop.App.Runtime.win-arm64' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r 'Microsoft.WindowsDesktop.App.Runtime.win-arm64' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Microsoft.WindowsDesktop.App.Runtime.win-arm64を grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64 to 8.0.32ステージング環境で 8.0.32 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
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3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- web github.com
- web github.com
- web github.com
- web github.com
- web secure@microsoft.com