CVE-2026-27588: GO-2026-4541 - Caddy MatchHost becomes case-sensitive in github.com/caddyserver/caddy/v2

CVE-2026-27588 · Severity: medium · CVSS 4 · Published 2026-02-26

Caddy MatchHost becomes case-sensitive in github.com/caddyserver/caddy/v2

Technologies: github.com/caddyserver/caddy/v2 (Go). Vendors: Go.

Quick answers

Is CVE-2026-27588 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-27588 being exploited in the wild.
How severe is CVE-2026-27588?
Medium severity, with a CVSS score of 4, published 26 February 2026.
Which products and versions are affected?
github.com/caddyserver/caddy/v2 (Go) SEMVER:introduced=0,fixed=2.11.1.
Is there a fix for CVE-2026-27588?
Yes. github.com/caddyserver/caddy/v2 (Go): upgrade to 2.11.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
Am I affected by CVE-2026-27588?
Check whether you run github.com/caddyserver/caddy/v2 (Go) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

  • github.com/caddyserver/caddy/v2 (Go): upgrade to 2.11.1 or later
    go get github.com/caddyserver/caddy/v2@v2.11.1

Affected products

  • github.com/caddyserver/caddy/v2 (Go) SEMVER:introduced=0,fixed=2.11.1

Identifiers

  • CVE-2026-27588
  • GHSA-x76f-jf84-rqj8
  • GO-2026-4541

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