Bug 2442408 (CVE-2026-27588) - CVE-2026-27588 github.com/caddyserver/caddy/v2/modules/caddyhttp: Caddy: Access control bypass due to case-sensitive host matching
Summary: CVE-2026-27588 github.com/caddyserver/caddy/v2/modules/caddyhttp: Caddy: Acce...
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Status: NEW
Alias: CVE-2026-27588
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
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Depends On: 2442435
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-02-24 17:05 UTC by OSIDB Bzimport
Modified: 2026-02-24 21:31 UTC (History)
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Description OSIDB Bzimport 2026-02-24 17:05:58 UTC 
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.
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