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.NET NuGet

GHSA-c55g-rp4x-fx84

Microsoft DirectX: .spritefont multiply overflow only in 32-bit builds

Published
May 18, 2026
Updated
May 18, 2026
Affected
2 pkgs
Patched
2 / 2
Exploits
None indexed

Blast Radius

2 pkgs affected
.NETdirectxtk_desktop_win10.NETdirectxtk_uwp

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects NuGet packages — download data is not available via public APIs for these ecosystems.

Description

Impact

The spritefont reader can be induced to perform a 32-bit overflow multiply that could in theory result in a RCE.

This impacts the use of the DirectX Tool Kit SpriteFont class file loading ctor if given untrusted data files.

Note this only applies to x86/ARM builds of the library. ARM64 and x64 native is not subject to this issue.

Patches

This bug has been fixed in the May 7, 2026 release. Alternatively, users can update their copy of the reader as per this commit.

Workarounds

This does not apply if a project's .spritefont files are all 'trusted' data that were included with an application. It's primarily an issue only if developers are using user-provided or network downloaded spritefont files.

Affected Packages

2 total 2 fixed
EcosystemPackageVulnerable rangeFix
.NETNuGetdirectxtk_desktop_win10all versions2026.5.8.1
.NETNuGetdirectxtk_uwpall versions2026.5.8.1

Detection & mitigation playbook

Open-source dependency
  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for directxtk_desktop_win10. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

  2. Fix

    Update directxtk_desktop_win10 to 2026.5.8.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-c55g-rp4x-fx84 is resolved across your whole dependency graph.

  3. Workarounds

    If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

  4. How O3 protects you

    O3 pinpoints whether GHSA-c55g-rp4x-fx84 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to GHSA-c55g-rp4x-fx84. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

### Impact The spritefont reader can be induced to perform a 32-bit overflow multiply that could in theory result in a RCE. This impacts the use of the *DirectX Tool Kit* **SpriteFont** class file loading ctor if given untrusted data files. > Note this only applies to x86/ARM builds of the library. ARM64 and x64 native is not subject to this issue. ### Patches This bug has been fixed in the May 7, 2026 release. Alternatively, users can update their copy of the reader as per [this commit](https://github.com/microsoft/DirectXTK/commit/ef1bd5d7f492c39dd0cd87493ba8ea38725c9791). ### Workaround
O3 Security · Impact-Aware SCA

Is GHSA-c55g-rp4x-fx84 in your dependencies?

O3 detects GHSA-c55g-rp4x-fx84 across NuGet dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.