Severity: HighAction: Patch

Microsoft releases emergency .NET patches for critical Brotli flaw

Microsoft released emergency .NET security updates to patch a critical vulnerability known as Broccoli2Shell, also tracked as Node2Shell and HTTP2Shell.

Excerpt from the primary source: BleepingComputer

Who is affected

Security professionals

What you should do · Patch

Apply the vendor's security update for the affected products. Check the linked advisory for affected and fixed versions, and put internet-facing systems first.

Automated guidance based on this story's classification. Check the linked advisories for specifics.

Sources

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Original reporting

Microsoft releases emergency .NET patches for critical Brotli flaw BleepingComputer · bleepingcomputer.com · Oct 26, 2026 · Primary source
Severity: HighAction: Patch

Critical 'HTTP2Shell' Brotli vulnerability triggers emergency patches

A critical flaw dubbed 'HTTP2Shell' in Brotli, the C decoder library built into Node.js, could allow attackers to corrupt memory and access sensitive data.

Patch

Apply the vendor's security update for the affected products.

Severity: ElevatedAction: Be aware

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