Cloudflare Fixes Zero-Day Flaw That Allowed Attackers To Bypass Web…

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Cloudflare Fixes Zero-Day Flaw That Allowed Attackers To Bypass Web…

Linkedin • January 19, 2026

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Cases like this show how even well-intentioned design choices can create unexpected attack paths. The abuse of an ACME validation route to bypass ...

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This article is one source in a clustered incident — the cluster page carries the summary, timeline and every other outlet covering it.

Cloudflare Zero-Day Flaw Exploited to Bypass Security Protections On October 9, 2025, security researchers from FearsOff discovered a zero-day flaw in Cloudflare that allowed attackers to bypass security protections by exploiting a specific certificate-validation request. The vulnerability involved the abuse of an ACME validation route, highlighting potential risks in design choices. 2 sources 71

Extracted Entities

Attack Types (1)

Zero-day Exploit

Tools (1)