CVE-2026-27588
Description
A flaw was found in Caddy's HTTP host request matcher. When Caddy is configured with a large list of host entries, its host matching becomes unexpectedly case-sensitive instead of case-insensitive as documented. A remote attacker can exploit this by altering the casing of the Host header in HTTP requests. This allows the attacker to bypass host-based routing and associated access controls, potentially gaining unauthorized access to resources.
Statement
Red Hat Product Security has determined that this vulnerability does not affect any currently supported Red Hat product. This assessment may evolve based on further analysis and discovery. For more information about this vulnerability and the products it affects, please see the linked references.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
Understanding the Weakness (CWE)
Access Control
Technical Impact: Bypass Protection Mechanism
Frequently Asked Questions
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