CVE-2026-39399 Details
Description
NuGet Gallery is a package repository that powers nuget.org. A security vulnerability exists in the NuGetGallery backend job’s handling of .nuspec files within NuGet packages. An attacker can supply a crafted nuspec file with malicious metadata, leading to cross package metadata injection that may result in remote code execution (RCE) and/or arbitrary blob writes due to insufficient input validation. The issue is exploitable via URI fragment injection using unsanitized package identifiers, allowing an attacker to control the resolved blob path. This enables writes to arbitrary blobs within the storage container, not limited to .nupkg files, resulting in potential tampering of existing content. This issue has been patched in commit 0e80f87628349207cdcaf55358491f8a6f1ca276.
A critical vulnerability has been identified in the NuGet Gallery backend's processing of .nuspec files within NuGet packages. This issue allows an attacker to inject malicious metadata into the nuspec file, leading to cross-package metadata injection. The vulnerability arises from inadequate input validation, enabling remote code execution (RCE) and/or arbitrary writes to blobs in the storage container. The exploitation involves URI fragment injection using unsanitized package identifiers, which can manipulate the resolved blob path and overwrite existing content. This vulnerability has been patched in the NuGet Gallery repository.
Users are advised to update to the patched version available in the NuGet Gallery repository.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Apr 15, 2026References to Advisories, Solutions, and Tools
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Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-20 | Improper Input Validation | [email protected] |
| CWE-22 | Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal') | [email protected] |
Affected Products
No affected product data is available for this CVE.
Change History
4 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 24, 2026 | CVE Translated | [email protected] |
| Jun 17, 2026 | CVE Modified | [email protected] |
| Jun 17, 2026 | CVE Modified | CISA-ADP |
| Apr 14, 2026 | New CVE Received | [email protected] |