CVE-2026-82726

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Source
https://cve.org/CVERecord?id=CVE-2026-82726
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82726.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-82726
Aliases
Published
2026-08-31T03:05:38Z
Modified
2026-09-03T03:30:18Z
Severity
  • 6.3 (Medium) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N CVSS Calculator
Summary
AshPhoenix get_subdomain maps a crafted or differently-cased Host header to an arbitrary tenant
Details

Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted Host header.

AshPhoenix.Helpers.get_subdomain/2 stripped the root domain with String.replace(host, ~r/.?#{root_host}/, ""). The root host was interpolated raw, so each . became a wildcard and any metacharacter a pattern, and the replace was global and unanchored, so a match was removed from anywhere in the string. With root_host example.com, Host: foo.exampleXcom.attacker.net returned the tenant foo.attacker.net. A metacharacter-bearing or nil root host degraded the pattern or raised on every request. The comparison was also case-sensitive, so TENANT.EXAMPLE.COM and EXAMPLE.COM slipped past the root-host allowlist. conn.host comes from the client Host header. The fix matches the root host case-insensitively and only as an exact trailing suffix.

This issue affects ash_phoenix: from 2.1.26 before 2.3.25.

Database specific 
{
    "cna_assigner": "EEF",
    "cwe_ids": [
        "CWE-178",
        "CWE-625"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82726.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "9a5ea4d377bc263de321d79574872a3dfc4fb541"
                },
                {
                    "fixed": "8306f29e77526840c89f3cd244996ce7c0fa2cda"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}
References

Affected packages

Git / github.com/ash-project/ash_phoenix

Affected ranges

Type
GIT
Repo
https://github.com/ash-project/ash_phoenix
Events
Introduced
02277a84d03fb43bdcbbb63dd97f9f1727509d8f
Fixed
1e38e7dc8838426cc94656238d9208759c661c03
Fixed
8306f29e77526840c89f3cd244996ce7c0fa2cda
Database specific
Show details 
{
    "extracted_events": [
        {
            "introduced": "2.1.26"
        },
        {
            "fixed": "2.3.25"
        }
    ],
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

v2.*
v2.1.26
v2.2.0
v2.3.0
v2.3.1
v2.3.10
v2.3.11
v2.3.12
v2.3.13
v2.3.14
v2.3.15
v2.3.16
v2.3.17
v2.3.18
v2.3.19
v2.3.2
v2.3.20
v2.3.21
v2.3.22
v2.3.23
v2.3.24
v2.3.3
v2.3.4
v2.3.5
v2.3.6
v2.3.7
v2.3.8
v2.3.9

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82726.json"