{"id":80575,"date":"2026-06-15T15:46:25","date_gmt":"2026-06-15T12:16:25","guid":{"rendered":"https:\/\/afaghhosting.net\/blog\/cve-2026-49757-oauth2-oidc-account-takeover-in-ashauthentication-via-email-based-user-matching\/"},"modified":"2026-06-15T15:46:25","modified_gmt":"2026-06-15T12:16:25","slug":"cve-2026-49757-oauth2-oidc-account-takeover-in-ashauthentication-via-email-based-user-matching","status":"publish","type":"post","link":"https:\/\/afaghhosting.net\/blog\/cve-2026-49757-oauth2-oidc-account-takeover-in-ashauthentication-via-email-based-user-matching\/","title":{"rendered":"CVE-2026-49757 &#8211; OAuth2\/OIDC account takeover in AshAuthentication via email-based user matching"},"content":{"rendered":"<p>CVE ID :CVE-2026-49757<\/p>\n<p>  Published : June 15, 2026, 12:16 p.m. | 1\u00a0hour, 25\u00a0minutes ago<\/p>\n<p>  Description :Authentication Bypass by Spoofing vulnerability in team-alembic AshAuthentication allows account takeover of local users via OAuth2\/OIDC sign-in.<\/p>\n<p>AshAuthentication&#8217;s OAuth2 and OIDC family strategies matched the local user by email address (an upsert on the email field, or a user-defined sign-in filter) rather than by the OpenID Connect iss\/sub claim combination. Per OpenID Connect Core \u00a75.7, only iss\/sub uniquely and stably identifies an end-user; other claims, including email, MUST NOT be used as unique identifiers.<\/p>\n<p>A provider login presenting a victim&#8217;s email, including an unverified email, a reused email, or an account with email_verified: false, resolved to and signed in as the victim&#8217;s existing local account. An unauthenticated attacker who can register an account on any accepted OAuth provider with the victim&#8217;s email (or who benefits from provider-side email reuse or reclamation) obtains the victim&#8217;s full local privileges.<\/p>\n<p>The fix resolves users by the (strategy, sub) identity stored in a user identity resource, and only links a new sub to an existing local account by email when the provider&#8217;s email_verified claim is trusted (trust_email_verified?).<\/p>\n<p>This issue affects ash_authentication from 0.1.0 before 4.14.0 and from 5.0.0-rc.0 before 5.0.0-rc.10.<\/p>\n<p>  Severity: 9.2 | CRITICAL<\/p>\n<p>  Visit the link for more details, such as CVSS details, affected products, timeline, and more&#8230;\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>CVE ID :CVE-2026-49757 Published : June 15, 2026, 12:16 p.m. | 1\u00a0hour, 25\u00a0minutes ago Description :Authentication Bypass by Spoofing vulnerability in team-alembic AshAuthentication allows account takeover of local users via OAuth2\/OIDC sign-in. AshAuthentication&#8217;s OAuth2 and OIDC family strategies matched the local user by email address (an upsert on the email field, or a user-defined sign-in &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-80575","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/80575","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=80575"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/80575\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=80575"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=80575"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=80575"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}