How should we interpret CVSS severity scores?

CVSS estimates technical severity, but it does not automatically equal business risk. Prioritize using context like internet exposure, asset criticality, known exploitation, and whether compensating controls exist. A Medium CVSS on an exposed production system can be more urgent than a Critical on an isolated non-production host.

Vulnerability Database

Q: What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

Q: What's the difference between a vulnerability, an exploit, and a zero-day?

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. Risk increases sharply when exploitation becomes reliable or widespread.

Q: Why do vulnerabilities keep reappearing in our environment?

Recurring findings usually come from incomplete asset discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host.

Q: How do we prioritize remediation without burning out the team?

Use a repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress so remediation is steady, not reactive.

Q: How can SynScan help reduce vulnerability risk over time?

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.

399,854

Total vulnerabilities in the database

Microsoft Security Advisory CVE-2026-92707 - ASP.NET Core Denial of Service Vulnerability — Microsoft.AspNetCore.SignalR.Protocols.MessagePack

Improperly Controlled Sequential Memory Allocation

Executive summary

Microsoft is releasing this security advisory to provide information about a vulnerability in Microsoft.AspNetCore.SignalR.Protocols.MessagePack; MessagePack; MessagePack.Annotations; MessagePackAnalyzer. This advisory also provides guidance on what developers can do to update their applications to remove this vulnerability.

SignalR's MessagePack protocol can consume excessive memory while deserializing deeply nested attacker-controlled arrays, resulting in unauthenticated remote denial of service.

Announcement

Announcement for this issue can be found at https://github.com/dotnet/announcements/issues/473

CVSS Details

Version: 3.1
Severity: Moderate
Score: 5.3
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Weakness: CWE-1325 (Improperly Controlled Sequential Memory Allocation)

Affected Platforms

Platforms: Windows, Linux, macOS
Architectures: All

<a name="affected-packages"></a>Affected Packages

The vulnerability affects Microsoft .NET projects that use an affected package version listed below.

Package name | Affected version | Patched version ------------ | ---------------- | --------------- Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 10.0.0, <= 10.0.12 | 10.0.13 Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 11.0.0-preview.5, <= 11.0.0-rc.1 | 11.0.0-rc.2 Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 8.0.0, <= 8.0.31 | 8.0.32 Microsoft.AspNetCore.SignalR.Protocols.MessagePack | >= 9.0.0, <= 9.0.20 | 9.0.21

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 fix the issue please install the latest version of .NET. If you have installed one or more .NET SDKs through Visual Studio, Visual Studio will prompt you to update Visual Studio, which will also update your .NET SDKs.
If your application references the vulnerable package, update the package reference to the patched version. You can list the versions you have installed by running the dotnet --info command.

Once you have installed the updated runtime or SDK, restart your apps for the update to take effect.

Additionally, if you've deployed self-contained applications targeting any of the impacted versions, these applications are also vulnerable and must be recompiled and redeployed.

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

CVE-2026-92707

Acknowledgements

Anonymous

Revisions

V1.0 (10/13/2026): Advisory published.

Published: Oct 13, 2026
Updated: Oct 14, 2026
GHSA: GHSA-86xp-94pg-8r6r
Severity: Medium
Exploit:
CISA KEV:

CVSS v3:

Severity: Medium
Score: 5.3
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CWEs:

CWE-1325

Affected Software
References

Software	Affected versions
Microsoft.AspNetCore.SignalR.Protocols.MessagePack	`>= 10.0.0, < 10.0.13`
Microsoft.AspNetCore.SignalR.Protocols.MessagePack	`>= 11.0.0-preview.5, < 11.0.0-rc.2`
Microsoft.AspNetCore.SignalR.Protocols.MessagePack	`>= 8.0.0, < 8.0.32`
Microsoft.AspNetCore.SignalR.Protocols.MessagePack	`>= 9.0.0, < 9.0.21`

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Frequently Asked Questions

What is a Vulnerability (CVE) and why does it matter?

A security vulnerability is a weakness in software, hardware, or configuration that can be exploited to compromise confidentiality, integrity, or availability. Many vulnerabilities are tracked as CVEs (Common Vulnerabilities and Exposures), which provide a standardized identifier so teams can coordinate patching, mitigation, and risk assessment across tools and vendors.

CVSS (Common Vulnerability Scoring System) estimates technical severity, but it doesn't automatically equal business risk. Prioritize using context like internet exposure, affected asset criticality, known exploitation (proof-of-concept or in-the-wild), and whether compensating controls exist. A "Medium" CVSS on an exposed, production system can be more urgent than a "Critical" on an isolated, non-production host.

A vulnerability is the underlying weakness. An exploit is the method or code used to take advantage of it. A zero-day is a vulnerability that is unknown to the vendor or has no publicly available fix when attackers begin using it. In practice, risk increases sharply when exploitation becomes reliable or widespread.

Recurring findings usually come from incomplete Asset Discovery, inconsistent patch management, inherited images, and configuration drift. In modern environments, you also need to watch the software supply chain: dependencies, containers, build pipelines, and third-party services can reintroduce the same weakness even after you patch a single host. Unknown or unmanaged assets (often called Shadow IT) are a common reason the same issues resurface.

Use a simple, repeatable triage model: focus first on externally exposed assets, high-value systems (identity, VPN, email, production), vulnerabilities with known exploits, and issues that enable remote code execution or privilege escalation. Then enforce patch SLAs and track progress using consistent metrics so remediation is steady, not reactive.

SynScan combines attack surface monitoring and continuous security auditing to keep your inventory current, flag high-impact vulnerabilities early, and help you turn raw findings into a practical remediation plan.