Unauthenticated service interruption via SignalR buffer exhaustion
Published Mar 10, 2026 · Updated Mar 10, 2026
Uncontrolled resource consumption in ASP.NET Core 8.0, 9.0, and 10.0 allows remote attackers to interrupt SignalR servers. SignalR accepts a specially crafted network message that exhausts an internal buffer because the buffer's resource consumption is not bounded or throttled. No authentication or user interaction is required, and successful exploitation exhausts server resources until the service can no longer respond.
Summary
What happened
Uncontrolled resource consumption in ASP.NET Core 8.0, 9.0, and 10.0 allows remote attackers to interrupt SignalR servers. SignalR accepts a specially crafted network message that exhausts an internal buffer because the buffer's resource consumption is not bounded or throttled. No authentication or user interaction is required, and successful exploitation exhausts server resources until the service can no longer respond.
The record
- CVE
- CVE-2026-26130
- Published
- Mar 10, 2026
- Updated
- Mar 10, 2026
- Vendor
- Microsoft
- Product
- ASP.NET Core 8.0
- Classifications
- CWE-770, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 10, 2026CVE publishedPublication date reported by the CVE source.
- Mar 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=8.0 <8.0.25
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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