GHSA-mmjf-rqrv-855v BIT-dotnet-2026-50527 BIT-dotnet-sdk-2026-50527 CVE-2026-50527
Microsoft Security Advisory CVE-2026-50527 – .NET Denial of Service Vulnerability
- Severity
- 7.5 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 1.17%
- Chance of exploitation in the next 30 days. Higher than 67.53% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- CWE-121 Stack-based Buffer Overflow
- Fix
10.0.10- Upgrade System.Security.Cryptography.Xml to this version or later
Description
Executive summary
Microsoft is releasing this security advisory to provide information about a vulnerability in .NET XML Encryption (System.Security.Cryptography.Xml). This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.
A denial of service vulnerability exists in the XML encryption implementation (EncryptedXml) in .NET 8, .NET 9, and .NET 10. An attacker could exploit this vulnerability by supplying crafted encrypted XML that is improperly validated, resulting in denial of service.
Announcement
Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/416
CVSS Details
- Version: 3.1
- Severity: High
- Score: 7.5
- Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness: CWE-121 (Stack-based Buffer Overflow)
Affected Platforms
- Platforms: All
- Architectures: All
<a name="affected-packages"></a>Affected Packages
The vulnerability affects any Microsoft .NET project if it uses any of affected package versions listed below
<a name=".NET 10.0"></a>.NET 10.0
| Package name | Affected version | Patched version |
|---|---|---|
| System.Security.Cryptography.Xml | >= 10.0.0, <= 10.0.9 | 10.0.10 |
<a name=".NET 9.0"></a>.NET 9.0
| Package name | Affected version | Patched version |
|---|---|---|
| System.Security.Cryptography.Xml | >= 9.0.0, <= 9.0.17 | 9.0.18 |
<a name=".NET 8.0"></a>.NET 8.0
| Package name | Affected version | Patched version |
|---|---|---|
| System.Security.Cryptography.Xml | >= 8.0.0, <= 8.0.3 | 8.0.4 |
Advisory FAQ
<a name="how-affected"></a>How do I know if I am affected?
If using a package listed in affected packages, you're exposed to the vulnerability.
<a name="how-fix"></a>How do I fix the issue?
To update the System.Security.Cryptography.Xml NuGet package, use one of the following methods:
NuGet Package Manager UI in Visual Studio:
- Open your project in Visual Studio.
- Right-click on your project in Solution Explorer and select "Manage NuGet Packages..." or navigate to "Project > Manage NuGet Packages".
- In the NuGet Package Manager window, select the "Updates" tab. This tab lists packages with available updates from your configured package sources.
- Select the package(s) you wish to update. You can choose a specific version from the dropdown or update to the latest available version.
- Click the "Update" button.
Using the NuGet Package Manager Console in Visual Studio:
- Open your project in Visual Studio.
- Navigate to "Tools > NuGet Package Manager > Package Manager Console".
- To update a specific package to its latest version, use the following Update-Package command:
Update-Package -Id System.Security.Cryptography.Xml
Using the .NET CLI (Command Line Interface):
- Open a terminal or command prompt in your project's directory.
- To update a specific package to its latest version, use the following add package command:
dotnet add package System.Security.Cryptography.Xml
Once you have updated the nuget package reference you must recompile and deploy your application. Additionally we recommend you update your runtime and/or SDKs, but it is not necessary to patch the vulnerability.
Other Information
Reporting Security Issues
If you have found a potential security issue in a supported version of .NET, please report it to the Microsoft Security Response Center (MSRC) via the MSRC Researcher Portal. Further information can be found in the MSRC Report an Issue FAQ.
Security reports made through MSRC may qualify for the Microsoft .NET Bounty. Details of the Microsoft .NET Bounty Program including terms and conditions are at https://aka.ms/corebounty.
Support
You can ask questions about this issue on GitHub in the .NET GitHub organization. The main repos are located at https://github.com/dotnet/runtime. The Announcements repo (https://github.com/dotnet/Announcements) will contain this bulletin as an issue and will include a link to a discussion issue. You can ask questions in the linked discussion issue.
Disclaimer
The information provided in this advisory is provided "as is" without warranty of any kind. Microsoft disclaims all warranties, either express or implied, including the warranties of merchantability and fitness for a particular purpose. In no event shall Microsoft Corporation or its suppliers be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages, even if Microsoft Corporation or its suppliers have been advised of the possibility of such damages. Some states do not allow the exclusion or limitation of liability for consequential or incidental damages so the foregoing limitation may not apply.
External Links
Acknowledgements
Levi Broderick with Microsoft
Revisions
V1.0 (July 14, 2026): Advisory published.
Affected versions
NuGet
| Package | Vulnerable | Fixed in |
|---|---|---|
| System.Security.Cryptography.Xml | >= 10.0.0, < 10.0.10 |
10.0.10 |
| System.Security.Cryptography.Xml | >= 9.0.0, < 9.0.18 |
9.0.18 |
| System.Security.Cryptography.Xml | >= 8.0.0, < 8.0.4 |
8.0.4 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
System.Security.Cryptography.Xml NuGet → 10.0.10
- dotnet
dotnet add package System.Security.Cryptography.Xml --version 10.0.10
Severity breakdown
CVSS 3.1 7.5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Weakness
CWE-121: Stack-based Buffer Overflow
A stack-based buffer overflow condition is a condition where the buffer being overwritten is allocated on the stack (i.e., is a local variable or, rarely, a parameter to a function).
How to prevent it
- Operation, Build and Compilation: Use automatic buffer overflow detection mechanisms that are offered by certain compilers or compiler extensions. Examples include: the Microsoft Visual Studio /GS flag, Fedora/Red Hat FORTIFY_SOURCE GCC flag, StackGuard, and ProPolice, which provide various mechanisms including canary-based detection and range/index checking. D3-SFCV (Stack Frame Canary Validation) from D3FEND [REF-1334] discusses canary-based detection in detail.
- Architecture and Design: Use an abstraction library to abstract away risky APIs. Not a complete solution.
- Implementation: Implement and perform bounds checking on input.
- Implementation: Do not use dangerous functions such as gets. Use safer, equivalent functions which check for boundary errors.
- Operation, Build and Compilation: Run or compile the software using features or extensions that randomly arrange the positions of a program's executable and libraries in memory. Because this makes the addresses unpredictable, it can prevent an attacker from reliably jumping to exploitable code. Examples include Address Space Layout Randomization (ASLR) [REF-58] [REF-60] and Position-Independent Executables (PIE) [REF-64]. Imported modules may be similarly realigned if their default memory addresses conflict with other modules, in a process known as "rebasing" (for Windows) and "prelinking" (for Linux) [REF-1332] using randomly generated addresses. ASLR for libraries cannot be used in conjunction with prelink since it would require relocating the libraries at run-time, defeating the whole purpose of prelinking. For more information on these techniques see D3-SAOR (Segment Address Offset Randomization) from D3FEND [REF-1335].
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-7hqp-7c5m-4vq6 Microsoft Security Advisory CVE-2026-96960 - .NET and Visual Studio Denial of Service Vulnerability | High | Also affects System.Security.Cryptography.Xml |
| GHSA-c399-9853-6jmj Microsoft Security Advisory CVE-2026-96959 - .NET and Visual Studio Denial of Service Vulnerability | High | Also affects System.Security.Cryptography.Xml |
| GHSA-r955-8q5j-3h83 Microsoft Security Advisory CVE-2026-96958 - .NET and Visual Studio Denial of Service Vulnerability | High | Also affects System.Security.Cryptography.Xml |
| GHSA-vrv5-2jg9-4mmr Microsoft Security Advisory CVE-2026-96222 - .NET Spoofing Vulnerability | High | Also affects System.Security.Cryptography.Xml |
| GHSA-23rf-6693-g89p Microsoft Security Advisory CVE-2026-50648 – .NET Denial of Service Vulnerability | High | Also affects System.Security.Cryptography.Xml |
| GHSA-8q5v-6pqq-x66h Microsoft Security Advisory CVE-2026-50525 – .NET Denial of Service Vulnerability | High | Also affects System.Security.Cryptography.Xml |
| GHSA-g8r8-53c2-pm3f Microsoft Security Advisory CVE-2026-47304 – .NET Security Feature Bypass Vulnerability | Critical | Also affects System.Security.Cryptography.Xml |
| GHSA-cvvh-rhrc-wg4q Microsoft Security Advisory CVE-2026-47302 – .NET Denial of Service Vulnerability | High | Also affects System.Security.Cryptography.Xml |
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