CVE-2026-82755mediumCWE-524

CVE-2026-82755: fallo de gravedad media en ash-project ash_authentication_oauth2_server

ash_authentication_oauth2_server serves tenant-specific OAuth metadata as publicly cacheable without Vary, enabling cross-tenant confusion

Publicada el · Actualizada el

Seguir esta CVE+ Monitorear ash authentication oauth2 server+ Monitorear ash_authentication_oauth2_server

Aviso por correo cuando entre en el KEV, tenga PoC pública o suba de nota.

13Vexday Risk Score

Sin señal de explotación. Ningún artefacto público de explotación conocido hasta ahora.

ssvc Trackcvss 6.3epss 0.7%
Use of Cache Containing Sensitive Information vulnerability in ash-project ash_authentication_oauth2_server allows a shared HTTP cache to serve one tenant's OAuth discovery metadata to another tenant's clients. The RFC 8414 and RFC 9728 metadata endpoints in AshAuthentication.Phoenix.Oauth2Server.ProtocolRouter return tenant-specific values (issuer, authorization_endpoint, token_endpoint, jwks_uri) when a tenant is set, but sent them with Cache-Control: public, max-age=3600 and no Vary. When the tenant is derived from something other than the URL (a header or the Host) and a shared cache sits in front, the cache key is the URL alone, so a stored response for one tenant is served to another for up to an hour. Affected clients may then send authorization codes and secrets to the wrong tenant's token endpoint and validate tokens against the wrong keys. This issue affects ash_authentication_oauth2_server: from 0.1.3 before 0.3.1.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:L/SA:N
Productos afectados
ash-project · ash_authentication_oauth2_server
CVEs relacionadas — ash-project ash_authentication_oauth2_server

En el mismo producto, de las más peligrosas a las menos.

CVE-2026-82754MEDIUMash_authentication_oauth2_server aliases every protocol endpoint under /.well-known, bypassing path-scoped controlsEPSS 0.7%CVE-2026-82758MEDIUMash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpointEPSS 0.7%CVE-2026-82756MEDIUMash_authentication_oauth2_server interpolates a tenant-derived value into the WWW-Authenticate challenge without escaping, allowing header parameter injectionEPSS 0.7%CVE-2026-82757MEDIUMash_authentication_oauth2_server CIMD fetcher classifies IPv4-in-IPv6 and site-local addresses as public, allowing SSRFEPSS 0.7%CVE-2026-82753HIGHUnauthenticated authorize requests create unbounded, never-expiring CIMD client rows and cache entries in ash_authentication_oauth2_serverEPSS 0.7%