{"id":"CVE-2026-82758","title":"Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\nresolve_secret…","summary":"Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\nresolve_secret…","severity":"medium","cvss":6.3,"cvssVector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","cwe":["CWE-287"],"vendor":"ash-project","product":"ash_authentication_oauth2_server","affected":["ash_authentication_oauth2_server >= 0.1.0 < 0.3.1","ash-project/ash_authentication_oauth2_server >= 855b578037c5ded18e8a6e60f42e56bde4905fae < 30a87101871775d27d79f9ad6f29eafa4779e118"],"published":"2026-09-07","updated":"2026-09-08","sourceUpdated":"2026-09-08T15:18:50.977","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-82758","references":[{"url":"https://cna.erlef.org/cves/CVE-2026-82758.html","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-82758","label":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}],"tags":["nvd","cve.org"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-09-08T14:40:53.437993Z"},"cvssSource":"cna","epss":0.00382,"epssPercentile":0.32108,"ingestedAt":"2026-09-08T15:33:26.980Z","slug":"CVE-2026-82758","body":"## Overview\n\nImproper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\nresolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or \"\" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":35,"depthScoreParts":{"impact":34.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}