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Advisory record · GHSA-gwq6-fmvp-qp68

Microsoft Security Advisory CVE-2025-55248: .NET Information Disclosure Vulnerability

CVSS 4.8 MediumEPSS 0.0074 · 54th percentile

Published by the GitHub Advisory Database at 15 Oct 2025, 17:39 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
Microsoft.NetCore.App.Runtime.linux-armNuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.linux-arm64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.linux-musl-armNuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.linux-musl-arm64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.linux-musl-x64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.linux-x64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.osx-arm64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.osx-x64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.win-armNuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.win-arm64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.win-x64NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Microsoft.NetCore.App.Runtime.win-x86NuGet>=9.0.0, <9.0.10 || >=8.0.0, <8.0.219.0.10, 8.0.21
Identifiers
GHSA-gwq6-fmvp-qp68 · BIT-dotnet-2025-55248 · BIT-dotnet-sdk-2025-55248 · CVE-2025-55248
Weakness (CWE)
CWE-326
Tags
Published
15 Oct 2025
Updated
10 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

The Microsoft.NetCore.App.Runtime packages for linux, linux-musl, osx and win platforms (including arm, arm64, x64 and x86 variants) are affected in .NET 8.0 versions from 8.0.0 through 8.0.20 and .NET 9.0 versions from 9.0.0 through 9.0.9. A man-in-the-middle attacker can prevent TLS from being used between a client and an SMTP server, forcing the client to send data unencrypted. Upgrade to 8.0.21 or 9.0.10; no workaround is listed.

Written 9 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
4.8 Medium 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:N/A:N/E:U/RL:O/RC:C CNA (microsoft)
  • CISA KEV Not listed.
  • EPSS 0.0074, the 54th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 14 Oct 2025, 22:11 UTC Published by the maintainers as a GitHub repository advisory
  2. 31 Oct 2026, 15:21 UTC First seen by agentprime
  3. 31 Oct 2026, 15:21 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.