Out-of-Bounds Write in Microsoft.WindowsDesktop.App.Runtime.win-arm64 (CVE-2026-70354)
Summary
Out-of-bounds write in Microsoft.WindowsDesktop.App.Runtime.win-arm64 (CVE-2026-70354). Successful exploitation can lead to full system takeover. Mitigation: upgrade to 8.0.30 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 Windows Presentation Foundation. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
An out-of-bounds write in .NET allows an unauthorized attacker to execute code locally.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/432
CVSS Details
- Version: 3.1
- Severity: High
- Score: 7.8
- Vector:
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C - Weakness: CWE-787: Out-of-bounds Write
Affected Platforms
- Platforms: Windows
- Architectures: All
Affected Packages
The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below
.NET 10
| Package name | Affected version | Patched version |
|---|---|---|
| Microsoft.WindowsDesktop.App.Runtime.win-arm64 | >= 10.0.0, <= 10.0.10 | 10.0.11 |
| Microsoft.WindowsDesktop.App.Runtime.win-x64 | >= 10.0.0, <= 10.0.10 | 10.0.11 |
| Microsoft.WindowsDesktop.App.Runtime.win-x86 | >= 10.0.0, <= 10.0.10 | 10.0.11 |
.NET 9
Package name…
Source: NIST National Vulnerability Database 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-2026-70354 has been found in Microsoft.WindowsDesktop.App.Runtime.win-arm64.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: upgrade Microsoft.WindowsDesktop.App.Runtime.win-arm64 to 8.0.30 or later.
If unsure, ask your IT team or search "Microsoft.WindowsDesktop.App.Runtime.win-arm64 CVE-2026-70354" on the vendor's site.
CVE-2026-70354 (Microsoft.WindowsDesktop.App.Runtime.win-arm64) — CWE-787 / CVSS v3 7.8
Attack vector: local / unauthenticated
Patched: 8.0.30 — 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 7.8/10). Successful exploitation can lead to full system takeover.
Update to 8.0.30.
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
-
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 8.0.30ステージング環境で 8.0.30 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。
-
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
- patch secure@microsoft.com
- web github.com
- web nvd.nist.gov
- web github.com
- web github.com