CVE-2026-27588
Caddy is an extensible server platform that uses TLS by default.
Published Feb 24, 2026 · updated Jun 17, 2026 · caddyserver caddy
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP 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 header. Version 2.11.1 contains a fix for the issue.
Code
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Timeline
Detection, updates, and resolution for this record.
Feb 24, 2026 · NIST NVD
Detected
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP 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 header.
Jun 17, 2026 · NIST NVD
Updated
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP 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 header.
Affected
- cpe caddyserver/caddyversion unspecified
Sources
- NIST NVDVulnerability recordCVE-2026-27588
Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's HTTP 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.
nvd.nist.gov