High 7.7Published Feb 24, 2026

CVE-2026-27588Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass

Updated under an hour ago (Oct 27, 2026, 2:50 AM ET)

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It affects caddyserver caddy. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for caddyserver caddy

Exploited in the last 30 days

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.

CVSS: 7.7 HIGH (v4.0, CNA)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
Weakness (CWE): CWE-178
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Feb 27, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

caddyserver caddy caddyserver:caddy (from the name)	before 2.11.1	CNA record
caddyserver caddy caddyserver:caddy	from 2.10.2 before 2.11.1	NVD

References

References

https://github.com/caddyserver/caddy/security/advisories/GHSA-x76f-jf84-rqj8	x-refsource-confirm, exploit, vendor-advisory
https://github.com/caddyserver/caddy/releases/tag/v2.11.1	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.