CVE-2026-82754

ash_authentication_oauth2_server aliases every protocol endpoint under /.well-known, bypassing path-scoped controls

Published: Sep 7, 2026Updated: Sep 8, 2026 Sources: CVE List NVDCWE-424

N/ACVSS

NVD MITRE

Description

Improper Protection of Alternate Path vulnerability in ash-project ash_authentication_oauth2_server exposes the state-changing OAuth endpoints under an unintended URL prefix, bypassing controls scoped to the canonical prefix. oauth2_server_protocol_routes/1 in AshAuthentication.Phoenix.Oauth2Server.Router forwards the same ProtocolRouter at both the /oauth prefix and the /.well-known prefix. Phoenix forward strips the matched prefix before dispatch, so the full route table answers under both mounts, and POST /register, POST /token, and POST /revoke are reachable as /.well-known/register, /.well-known/token, and /.well-known/revoke. Edge controls such as WAF rules, rate limits, or authentication exemptions written against the /oauth paths, or that allow-list /.well-known as unauthenticated, do not apply to the alias. This issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.

No summary for this CVE yet.

Weaknesses

CWE-424

Affected Products

ash-project

oss-projectaka ash_postgres, ash_authentication_phoenix, ash

ash_authentication_oauth2_serverLibrary

OSS Libraries

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

References

https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-wwxg-h779-3wf4

github.com

https://cna.erlef.org/cves/CVE-2026-82754.html

cna.erlef.org

https://osv.dev/vulnerability/EEF-CVE-2026-82754

osv.dev

and 1 more references View all →

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