Microsoft DirectX: .spritefont multiply overflow only in 32-bit builds
Key facts
- Attack vector
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- Privileges required
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- User interaction
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- Attack complexity
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- Impact type
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- Confidentiality · integrity · availability
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- Fix status
- Fixed
No CVSS vector from any source. Fix status from GitHub.
Summary
### 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). ### 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.
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | directxtk_desktop_win10 (NuGet) | before 2026.5.8.1 | 2026.5.8.1 | Patch available | GHSA-c55g-rp4x-fx84 |
| — | directxtk_uwp (NuGet) | before 2026.5.8.1 | 2026.5.8.1 | Patch available | GHSA-c55g-rp4x-fx84 |
- directxtk_desktop_win10 (NuGet) Vendor— Affected before 2026.5.8.1 Fixed in 2026.5.8.1 Patch available GHSA-c55g-rp4x-fx84
- directxtk_uwp (NuGet) Vendor— Affected before 2026.5.8.1 Fixed in 2026.5.8.1 Patch available GHSA-c55g-rp4x-fx84
Remediation
- Fix · GHSA-c55g-rp4x-fx84 directxtk_desktop_win10 (NuGet) Fixed in 2026.5.8.1 Advisory →
- Fix · GHSA-c55g-rp4x-fx84 directxtk_uwp (NuGet) Fixed in 2026.5.8.1 Advisory →
Timeline
- 2026-10-03 Threatist record created from GHSA-c55g-rp4x-fx84
References
Sources
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences