Answer in brief
CVE-2026-82726 records a Medium severity (CVSS 6.3) vulnerability in AshPhoenix get_subdomain maps a crafted or differently-cased Host header to an arbitrary tenant. The current sources do not mark it as known exploited. The current feed maps ash-project/ash_phoenix (generic), ash-project/ash_phoenix (generic), ash-project/ash-project/ash_phoenix (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps ash-project/ash_phoenix (generic), ash-project/ash_phoenix (generic), ash-project/ash-project/ash_phoenix (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| ash-project/ash_phoenixgeneric | >=9a5ea4d377bc263de321d79574872a3dfc4fb541 <8306f29e77526840c89f3cd244996ce7c0fa2cda | 8306f29e77526840c89f3cd244996ce7c0fa2cda |
| ash-project/ash_phoenixgeneric | >=2.1.26 <2.3.25 | 2.3.25 |
| ash-project/ash-project/ash_phoenixgeneric | >=9a5ea4d377bc263de321d79574872a3dfc4fb541 <8306f29e77526840c89f3cd244996ce7c0fa2cda | 8306f29e77526840c89f3cd244996ce7c0fa2cda |
Published upstream
Aug 31, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Aug 31, 2026
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.
Quoted source text, attributed separately from HOL analysis.