CVE-2026-82726: AshPhoenix get_subdomain maps a crafted or differently-cased Host header to an arbitrary tenant
ash-project · ash_phoenix
Fixed in 2.3.25 · Affected: ash-project ash_phoenix before 2.3.25 · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 45% of scored CVEs
DescriptionCVE.org
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.
Affected products2
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- ash-project · ash_phoenixfrom 2.1.26 before 2.3.25
- ash-project · ash_phoenixVersions not stated
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- ash-project
- Published
- August 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-82726 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.