CVE-2026-49757
Authentication Bypass by Spoofing vulnerability in team-alembic AshAuthentication allows account takeover of local users via OAuth2/OIDC sign-in.
Overview
CVE-2026-49757 is a known-severity vulnerability. It was published on June 15, 2026.
Technical description
Authentication Bypass by Spoofing vulnerability in team-alembic AshAuthentication allows account takeover of local users via OAuth2/OIDC sign-in.
AshAuthentication'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 §5.7, only iss/sub uniquely and stably identifies an end-user; other claims, including email, MUST NOT be used as unique identifiers.
A provider login presenting a victim's email, including an unverified email, a reused email, or an account with email_verified: false, resolved to and signed in as the victim's existing local account. An unauthenticated attacker who can register an account on any accepted OAuth provider with the victim's email (or who benefits from provider-side email reuse or reclamation) obtains the victim's full local privileges.
The fix resolves users by the (strategy, sub) identit
Remediation
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
References
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Frequently asked questions
What is CVE-2026-49757?
CVE-2026-49757 is a known-severity vulnerability. It was published on June 15, 2026.
How severe is CVE-2026-49757?
CVSS score information is not yet available for this vulnerability. Check back as the CVE record is updated by NVD analysts.
How do I fix or remediate CVE-2026-49757?
Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2026-49757?
CyberStrike is an open-source, AI-augmented pentesting engine. Rather than flag a version number, it tests whether an issue like CVE-2026-49757 is actually reachable in your own applications and APIs, then verifies each finding before reporting it. That tells you if the weakness is a real, exploitable risk in your environment or a false positive you can safely deprioritize.