CISA says attackers are exploiting HTTP2Shell, a critical Brotli flaw in Node.js and other software
The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added CVE-2026-111497, a flaw in Google's Brotli compression library known as HTTP2Shell, to its catalog of exploited vulnerabilities on October 27, 2026. Crafted compressed data can crash affected software, expose its memory, or in some cases let an attacker run code. The flaw affects Node.js, Python packages, .NET, and other software built on Brotli. U.S. federal civilian agencies must fix it by November 10.