CVE-2026-27588

Summary

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP host request matcher is documented as case-insensitive, but when configured with a large host list (>100 entries) it becomes case-sensitive due to an optimized matching path. An attacker can bypass host-based routing and any access controls attached to that route by changing the casing of the Host header. Version 2.11.1 contains a fix for the issue.

Affected Software

VendorProductVersion RangeStatus
caddyservercaddy< 2.11.1affected

Weaknesses

  • CWE-178: CWE-178: Improper Handling of Case Sensitivity

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: poc
    • Automatable: yes
    • Technical Impact: partial

References