CVE-2026-32203: Stack-based Buffer Overflow in .NET Cryptography XML Processing
Vulnerability ID: CVE-2026-32203
CVSS Score: 7.5
Published: 2026-04-14
Microsoft .NET and Visual Studio contain a stack-based buffer overflow vulnerability within the System.Security.Cryptography.Xml library. The flaw occurs due to unbounded recursion when processing deeply nested XML-based cryptographic structures, allowing unauthenticated attackers to cause a Denial of Service (DoS) via process exhaustion.
TL;DR
Unbounded recursion in .NET's XML cryptography processing allows remote attackers to trigger a stack overflow and subsequent Denial of Service by supplying deeply nested XML elements.
Technical Details
- CWE ID: CWE-121 / CWE-20
- Attack Vector: Network
- CVSS 3.1 Base: 7.5
- EPSS Score: 0.13%
- Impact: Denial of Service (DoS)
- Exploit Status: None / Unproven
- CISA KEV: Not Listed
- Patch Status: Available
Affected Systems
- .NET 10.0
- .NET 9.0
- .NET 8.0
- Visual Studio 2022 v17.12
- Visual Studio 2022 v17.14
-
Microsoft .NET 10.0: <= 10.0.5 (Fixed in:
10.0.6) -
Microsoft .NET 9.0: <= 9.0.14 (Fixed in:
9.0.15) -
Microsoft .NET 8.0: <= 8.0.25 (Fixed in:
8.0.26) -
Microsoft Visual Studio 2022 v17.12: <= 17.12.18 (Fixed in:
17.12.19) -
Microsoft Visual Studio 2022 v17.14: <= 17.14.29 (Fixed in:
17.14.30)
Code Analysis
Commit: b234b9a
Introduces thread-local depth tracking for XML cryptography parsing to prevent stack overflow conditions.
Mitigation Strategies
- Apply official vendor patches to update the .NET framework and Visual Studio environments.
- Implement Web Application Firewall (WAF) rules to detect and drop deeply nested XML payloads.
- Enforce strict size limits on incoming XML requests to prevent large, nested payloads from reaching the application logic.
Remediation Steps:
- Identify all hosts running vulnerable versions of .NET 8.0, 9.0, 10.0, and Visual Studio 2022.
- Deploy .NET framework updates 8.0.26, 9.0.15, or 10.0.6 to affected servers.
- Update Visual Studio 2022 installations to 17.12.19 or 17.14.30.
- Restart the affected .NET processes or IIS worker processes to ensure the updated runtime assemblies are loaded.
- Monitor application logs for unhandled CryptographicException events related to recursion depth.
References
- Microsoft Security Response Center (MSRC) Advisory
- Red Hat Advisory
- .NET Runtime Fix Commit
- CVE.org Record
Read the full report for CVE-2026-32203 on our website for more details including interactive diagrams and full exploit analysis.
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