CVE-2026-27588CRITICAL 9.1EPSS p28.7%

CVE-2026-27588CVE-2026-27588

Description

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.

Scoring

CVSS 3.19.1 (CRITICAL)
VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
EPSS0.37% probability of exploitation · percentile 28.7% · 2026-06-18T12:00:27Z
Published2026-02-24
Last modified2026-02-25

Underlying weaknesses· 1

CWE-178

References

  1. https://github.com/caddyserver/caddy/releases/tag/v2.11.1
  2. https://github.com/caddyserver/caddy/security/advisories/GHSA-x76f-jf84-rqj8

1

TypeTargetConfidenceTier
WeaknessImproper Handling of Case Sensitivitycwe-1780%live

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Sourced from NVD + FIRST.org EPSS. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.