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CDN Tsunami Attack Abuses HTTP/3 Translation for Up to 350x DoS Amplification
Researchers disclosed two DoS attacks exploiting CDNs' HTTP/3-to-HTTP/1.1 translation to amplify low-bandwidth requests up to 350x against origin servers.
Researchers named the two techniques HTTP/3 Bandwidth Amplification (HBA) and HTTP/3 Connection Amplification (HCA), exploiting the gap where CDNs speak HTTP/3 to browsers but only HTTP/1.1 to origins. All six tested CDNs (Alibaba, Baidu, Cloudflare, CloudFront, Fastly, Tencent) were susceptible to HBA, and five to HCA, with Cloudflare immune to HCA because it buffers full requests before opening backend connections. Attackers using under 5 Mbps forced over 100 Mbps at origins, and the 350x factor applies only to Alibaba, Baidu, and Tencent, which support the QPACK dynamic table. Testing identified 42,330 potentially vulnerable subdomains out of 151,685 hosted on the six providers across the Tranco Top 1M.
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AWS Certificate Manager sets 2027 end date for email-validated certificate renewals
AWS Certificate Manager will phase out email validation for public certificates during 2027, requiring migration to DNS validation before September 30, 2027.
AWS Certificate Manager will stop offering email validation in new Regions on January 1, 2027, discontinue it for new certificate requests on March 31, 2027, and stop renewing email-validated certificates on September 30, 2027. This precedes the CA/Browser Forum's March 15, 2028 deadline ending email-based domain validation for publicly trusted certificates. AWS is updating the UpdateCertificateOptions API so customers can switch to DNS validation in place while retaining the certificate ARN, with Route 53 support for creating required CNAME records.
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Week in review: Linux rootkit deployed on F5 BIG-IP APM devices, Cisco FMC bugs exploited
Weekly roundup: Cisco FMC and N-able N-central zero-days exploited in the wild, MikroTik RouterOS hijacks, Microsoft Patch Tuesday ships two exploited zero-days.
State-sponsored and financially-motivated attackers are actively exploiting CVE-2026-20079, a critical authentication bypass in Cisco Secure Firewall Management Center (FMC), alongside CVE-2026-20316. N-able issued an emergency hotfix for CVE-2026-86218, a critical pre-auth RCE in the N-central RMM platform exploited in the wild. CERT Polska disclosed six RouterOS vulnerabilities being chained to hijack internet-exposed MikroTik devices. Microsoft's September 2026 Patch Tuesday shipped a record patch count including two zero-days, while roughly 67,000 Trezor customers faced phishing after a shipping-partner breach and researchers privately disclosed a zero-click WeChat worm to Tencent.
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