CVE-2026-58280 high CVSS 7.5

Vulnerability in Microsoft.NETCore.App.Runtime.linux-arm (CVE-2026-58280)

Summary

Vulnerability in Microsoft.NETCore.App.Runtime.linux-arm (CVE-2026-58280). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 11.0.0-rc.2 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 System.Security.Cryptography.Xml and System.Private.Xml. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

Signed XML fixes add input-depth and operation-count limits, prohibit DTD processing by default, validate entity references, bound encrypted-data candidate processing, and cap attributes and namespaces used by C14N transforms.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/447

CVSS Details

Version: 3.1
Severity: High
Score: 7.5
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness: CWE-674 (Uncontrolled Recursion)

Affected Platforms

Platforms: Windows, Linux, macOS
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.NETCore.App.Runtime.linux-arm	>= 9.0.0, <= 9.0.20	9.0.21
Microsoft.NETCore.App.Runtime.linux-arm64	>= 9.0.0, <= 9.0.20	9.0.21
[Microsoft.NETCore.App.Runtime.linux-musl-arm](https://www.nuget.org/pac…

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-2026-58280 has been found in Microsoft.NETCore.App.Runtime.linux-arm.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: upgrade Microsoft.NETCore.App.Runtime.linux-arm to 11.0.0-rc.2 or later.
If unsure, ask your IT team or search "Microsoft.NETCore.App.Runtime.linux-arm CVE-2026-58280" on the vendor's site.

CVE-2026-58280 (Microsoft.NETCore.App.Runtime.linux-arm) — CWE-674 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 11.0.0-rc.2 — 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.

❓ What is the problem

A vulnerability (CWE-674) exists in Microsoft.NETCore.App.Runtime.linux-arm.

📍 Affected scope

Check the vendor advisory for the affected versions of Microsoft.NETCore.App.Runtime.linux-arm.

🔥 Severity

Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to 11.0.0-rc.2.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Microsoft.NETCore.App.Runtime.linux-arm' . 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

1
Identify exposure identify
```
grep -r 'Microsoft.NETCore.App.Runtime.linux-arm' . | 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.NETCore.App.Runtime.linux-arm を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade Microsoft.NETCore.App.Runtime.linux-arm to 11.0.0-rc.2
```
ステージング環境で 11.0.0-rc.2 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。
3
Post-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。