Executive Risk Summary
"A security vulnerability exists in the NuGetGallery backend job's handling of .nuspec files, allowing an attacker to supply a crafted nuspec file with malicious metadata, leading to cross package metadata injection and potential remote code execution. This issue is exploitable via URI fragment injection using unsanitized package identifiers, enabling writes to arbitrary blobs within the storage container."
Anticipated Attack Path
- 1. Attacker crafts a malicious .nuspec file with malicious metadata
- 2. Attacker injects the malicious .nuspec file into the NuGet package
- 3. NuGetGallery backend job processes the malicious .nuspec file, leading to cross package metadata injection and potential remote code execution
Am I Vulnerable?
- Verify that the NuGetGallery backend job is updated to the latest version
- Check for any suspicious activity related to .nuspec file handling
- Monitor the storage container for any unauthorized writes to blobs
Operational Audit Arsenal
Target Type Service
Target Asset NuGetGallery
Standard Path https://github.com/NuGet/NuGetGallery
PowerShell
# 🛠️ Senior Engineer Universal Audit
# Target: NuGetGallery (Service)
$Targets = 'NuGetGallery'
$SearchPaths = @("$env:windir\System32", "$env:ProgramFiles", "${env:ProgramFiles(x86)}")
Get-ChildItem -Path $SearchPaths -Include $Targets -Recurse -ErrorAction SilentlyContinue |
Select-Object FullName, @{Name="Version";Expression={$_.VersionInfo.ProductVersion}}Patch Impact Forecast
Reboot Required Unlikely
Low to moderate disruption expected, depending on the specific deployment and usage of NuGetGallery
Internal Work Notes
CVE-2026-39399: NuGet Gallery - Backend Job vulnerability allowing remote code execution and arbitrary blob writes, patched in commit 0e80f87628349207cdcaf55358491f8a6f1ca276
Technical Intelligence & Operational Utilities • Delivered Weekly
Intelligence Sources
Related Microsoft Threats
Data compiled from NVD, MSRC, and CISA KEV Catalog. Intelligence synthesized via AI. Scripts provided for diagnostic purposes under MIT License.