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CVE-2026-27588 (GCVE-0-2026-27588)

Vulnerability from cvelistv5 – Published: 2026-02-24 16:28 – Updated: 2026-02-27 20:47
VLAI
Title
Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass
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.
Severity
7.7 (High)
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:P
SSVC
Exploitation: poc Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-02-27 20:47 UTC
CWE
  • CWE-178 - Improper Handling of Case Sensitivity
Assigner
References
Impacted products
Vendor Product Version CPE status
caddyserver caddy Affected: < 2.11.1
guessed Create a notification for this product.
Show details on NVD website
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