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Vulnerabilities

Vulnerability · CVE-2026-39399

NuGet Gallery is a package repository that powers nuget.org.

Published Apr 14, 2026 · catalog updated Jul 24, 2026 · NuGet Gallery is a

Check if you run it

No confirmed exploitation is on record for CVE-2026-39399. EPSS is 0.82%. Act only if a listed version of NuGet Gallery is a is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (NuGet Gallery is a).
  • No version range is stored. A customer cannot check an installed version against this record.
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.6
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.82%
Remediation
Advisory link
Affected products
See sources for product scope

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.

No affected version ranges are stored yet. Use the vendor advisory before you decide this record does not apply.

How to fix CVE-2026-39399

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-39399. EPSS is 0.82%. Act only if a listed version of NuGet Gallery is a is installed.

Which versions are affected?

Affected version ranges are not on this record. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-20: Improper Input Validation; CWE-22: Path Traversal. EPSS 0.82%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Apr 14, 2026 · NIST NVD

    Detected

    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 validati

  2. Jul 24, 2026 · NIST NVD

    Updated

    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 validati

Sources

  • CVE.orgVulnerability recordCVE-2026-39399

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-39399

    30-day exploitation probability 0.8%

    first.org
  • NIST NVDVulnerability recordCVE-2026-39399

    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

    nvd.nist.gov

References

Freshness

Last verified in this catalog Oct 18, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.