Service interruption via unconstrained request decompression
Published Sep 8, 2026 · Updated Sep 9, 2026
Denial of service in Microsoft ASP.NET Core allows remote attackers to interrupt IIS-hosted services with compressed requests. The IIS middleware fails to constrain decompressed request size, allowing a small, highly compressed body to expand in memory until excess consumption prevents service. Exposure requires Windows IIS out-of-process hosting and request decompression; the reported consequence is service interruption rather than data access or modification.
Summary
What happened
Denial of service in Microsoft ASP.NET Core allows remote attackers to interrupt IIS-hosted services with compressed requests. The IIS middleware fails to constrain decompressed request size, allowing a small, highly compressed body to expand in memory until excess consumption prevents service. Exposure requires Windows IIS out-of-process hosting and request decompression; the reported consequence is service interruption rather than data access or modification.
The record
- CVE
- CVE-2026-69304
- Published
- Sep 8, 2026
- Updated
- Sep 9, 2026
- Vendor
- Microsoft
- Product
- ASP.NET Core 8.0
- Classifications
- CWE-409, T1499.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 8, 2026CVE publishedPublication date reported by the CVE source.
- Sep 9, 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 <8.0.31
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
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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