CVE-2026-27588

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Source
https://cve.org/CVERecord?id=CVE-2026-27588
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-27588.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-27588
Aliases
Downstream
Published
2026-02-24T16:28:28.106Z
Modified
2026-02-25T08:54:47.124961Z
Severity
  • 7.7 (High) CVSS_V4 - 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 CVSS Calculator
Summary
Caddy: MatchHost becomes case-sensitive for large host lists (>100), enabling host-based route/auth bypass
Details

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.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-178"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27588.json"
}
References

Affected packages

Git / github.com/caddyserver/caddy

Affected ranges

Type
GIT
Repo
https://github.com/caddyserver/caddy
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
6610e2f1bd8f54853006eefd3849c9965190e57f
Database specific 
{
    "versions": [
        {
            "introduced": "0"
        },
        {
            "fixed": "2.11.1"
        }
    ]
}

Affected versions

v2.*
v2.0.0
v2.0.0-beta.13
v2.0.0-beta.14
v2.0.0-beta.15
v2.0.0-beta.16
v2.0.0-beta.17
v2.0.0-beta.18
v2.0.0-beta.19
v2.0.0-beta.20
v2.0.0-beta1
v2.0.0-beta10
v2.0.0-beta11
v2.0.0-beta12
v2.0.0-beta2
v2.0.0-beta3
v2.0.0-beta4
v2.0.0-beta5
v2.0.0-beta6
v2.0.0-beta7
v2.0.0-beta8
v2.0.0-beta9
v2.0.0-rc.1
v2.0.0-rc.2
v2.0.0-rc.3
v2.1.0
v2.1.0-beta.1
v2.1.0-beta.2
v2.1.1
v2.10.0
v2.10.0-beta.1
v2.10.0-beta.2
v2.10.0-beta.3
v2.10.0-beta.4
v2.10.1
v2.10.2
v2.11.0
v2.11.0-beta.1
v2.11.0-beta.2
v2.2.0
v2.2.0-rc.1
v2.2.0-rc.2
v2.2.0-rc.3
v2.2.1
v2.2.3
v2.3.0
v2.3.0-beta.1
v2.3.0-rc.1
v2.3.0-rc.2
v2.4.0
v2.4.0-beta.1
v2.4.0-beta.2
v2.4.0-rc.1
v2.4.1
v2.4.2
v2.4.3
v2.4.4
v2.4.5
v2.4.6
v2.5.0
v2.5.0-beta.1
v2.5.0-rc.1
v2.5.1
v2.5.2
v2.6.0
v2.6.0-beta.1
v2.6.0-beta.2
v2.6.0-beta.3
v2.6.0-beta.4
v2.6.0-beta.5
v2.6.1
v2.6.2
v2.6.3
v2.6.4
v2.7.0
v2.7.0-beta.1
v2.7.0-beta.2
v2.7.1
v2.7.2
v2.7.3
v2.7.4
v2.7.5
v2.8.0
v2.8.0-beta.1
v2.8.0-beta.2
v2.8.0-rc.1
v2.8.1
v2.8.2
v2.8.3
v2.8.4
v2.9.0
v2.9.0-beta.1
v2.9.0-beta.2
v2.9.0-beta.3
v2.9.1

Database specific

source 
"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-27588.json"