CVE-2026-27590

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Source
https://cve.org/CVERecord?id=CVE-2026-27590
Import Source
https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2026-27590.json
JSON Data
https://api.test.osv.dev/v1/vulns/CVE-2026-27590
Aliases
Downstream
Related
Published
2026-02-24T16:33:41.353Z
Modified
2026-02-25T08:54:47.909072Z
Severity
  • 8.9 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:P CVSS Calculator
Summary
Caddy: Unicode case-folding length expansion causes incorrect split_path index (SCRIPT_NAME/PATH_INFO confusion) in FastCGI transport
Details

Caddy is an extensible server platform that uses TLS by default. Prior to version 2.11.1, Caddy's FastCGI path splitting logic computes the split index on a lowercased copy of the request path and then uses that byte index to slice the original path. This is unsafe for Unicode because strings.ToLower() can change UTF-8 byte length for some characters. As a result, Caddy can derive an incorrect SCRIPT_NAME/SCRIPT_FILENAME and PATH_INFO, potentially causing a request that contains .php to execute a different on-disk file than intended (path confusion). In setups where an attacker can control file contents (e.g., upload features), this can lead to unintended PHP execution of non-.php files (potential RCE depending on deployment). Version 2.11.1 fixes the issue.

Database specific 
{
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
        "CWE-180",
        "CWE-20"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/27xxx/CVE-2026-27590.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-2026-27590.json"