CVE-2026-82726— AshPhoenix get_subdomain maps a crafted or differently-cased Host header to an arbitrary tenant
Quick assessment
Affected
ash-project ash_phoenix
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.
漏洞描述翻译： Ash Phoenix 中的宽松正则表达式（Permissive Regular Expression）漏洞允许远程客户端通过发送精心构造的 请求头，来指定 Ash 应用所使用的租户（tenant），或导致请求性能下降。 使用 来剥离根域名。由于 被直接插值到正则表达式中，其中的每个 字符都会变成通配符，任何正则元字符（如 、 、 、 、 等）都会被解释为模式字符。此外，该替换操作是全局的且未加锚点（unanchored），因此匹配内容可能从字符串的任意位置被移除。 当 为 时，若客户端发送 ，系统
Possible ATT&CK Techniques 1 AI
T1010 · Application Window Discovery
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I. Basic Information for CVE-2026-82726
Vulnerability Information
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Vulnerability Title
AshPhoenix get_subdomain maps a crafted or differently-cased Host header to an arbitrary tenant
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
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
Source: CVE Program / CVE List V5
Vulnerability Type
宽松定义的正则表达式
Source: CVE Program / CVE List V5
Affected Products
| Vendor | Product | Affected Versions | CPE | Subscribe |
|---|---|---|---|---|
| ash-project | ash_phoenix | 2.1.26 ~ 2.3.25 |
cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*
|
|
| ash-project | ash_phoenix | 9a5ea4d377bc263de321d79574872a3dfc4fb541 ~ 8306f29e77526840c89f3cd244996ce7c0fa2cda |
cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*
|
|
II. Public POCs for CVE-2026-82726
| # | POC Description | Source Link | Shenlong Link |
|---|
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Other References for CVE-2026-82726 (3)
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🔗 EEF-CVE-2026-82726 - OSV related
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Same Patch Batch · ash-project · 2026-08-31 · 17 CVEs total
| CVE-2026-77956 | 10.0 CRITICAL | EEx template evaluation of prompt content in AshAi enables remote code execution |
| CVE-2026-77850 | 8.4 HIGH | Stored XSS in AshAdmin relationship typeahead via unescaped label_field content |
| CVE-2026-82673 | 8.3 HIGH | Path traversal in AshAdmin file uploads via unsanitized client filename |
| CVE-2026-82722 | 8.3 HIGH | AshAdmin LiveView events intern atoms from client input, exhausting the atom table (node D |
| CVE-2026-75757 | 8.3 HIGH | AshAdmin cookie reader matches names by substring, enabling actor/session shadowing from a |
| CVE-2026-82724 | 7.6 HIGH | Broken access control in AshPhoenix SubdomainHook via a nil tenant in handle_subdomain |
| CVE-2026-81315 | 7.4 HIGH | MCP DNS-rebinding origin check in AshAi is bypassed by a spoofed X-Forwarded-Proto header |
| CVE-2026-75760 | 7.1 HIGH | AshAi vectorize change leaks raw embedding-provider errors, including credentials, in a us |
| CVE-2026-82564 | 7.1 HIGH | Identity tool filter in AshAi accepts operator maps, allowing update or destroy of unident |
| CVE-2026-82579 | 6.0 MEDIUM | AshAi tool loop never terminates when all tool calls are filtered out, enabling denial of |
| CVE-2026-82580 | 5.3 MEDIUM | AshAi echoes raw tool exception messages into the conversation, disclosing internal detail |
| CVE-2026-82725 | 2.3 LOW | AshPhoenix FilterForm allows filtering across non-public relationships, disclosing private |
| CVE-2026-82727 | 2.3 LOW | AshPhoenix Form.Auto leaks submitted params in an unknown _union_type error message |
| CVE-2026-81853 | 2.3 LOW | AshAdmin composite primary key decoding accepts arbitrary fields, enabling a secret-attrib |
| CVE-2026-81852 | 2.1 LOW | AshAdmin ships a hardcoded CSP nonce, allowing nonce-based CSP bypass |
| CVE-2026-82681 | 2.0 LOW | Query-parameter injection in AshAdmin row-action links via unencoded string primary keys |
IV. Related Vulnerabilities
Same vendor: ash-project
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CVE-2026-82725
AshPhoenix FilterForm allows filtering across non-public rel -
CVE-2026-82724
Broken access control in AshPhoenix SubdomainHook via a nil -
CVE-2026-82727
AshPhoenix Form.Auto leaks submitted params in an unknown _u -
CVE-2026-82673
Path traversal in AshAdmin file uploads via unsanitized clie -
CVE-2026-81853
AshAdmin composite primary key decoding accepts arbitrary fi
Same weakness: CWE-625
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CVE-2026-19278
Stackrox: stackrox: privilege escalation via unanchored regu -
CVE-2026-64940
Nishishi Factory Tegalog -Fumy Otegaru Memo Logger 输入验证错误漏洞 -
CVE-2026-44587
CarrierWave has a denylisted_content_type bypass via Unescap -
CVE-2026-34830
Rack: Rack::Sendfile regex injection via HTTP_X_ACCEL_MAPPIN -
CVE-2026-34763
Rack: Rack::Directory info disclosure and DoS via unescaped
V. Comments for CVE-2026-82726
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