WordPress OAuth Plugin Identity Assertion Binding Flaw

The WP OAuth Server ( Login with WordPress ) WordPress plugin before 6.4.0 does not bind the OpenID Connect identity assertion it issues to the authorization grant being exchanged, returning instead the assertion belonging to whichever user authenticated most recently, which allows users with the Subscriber role and above to obtain a validly signed identity assertion for another user, including an administrator, and authenticate as them at any application that uses the site for single sign-on.

Casky was already ahead

This CVE exploits attack patterns that Casky's 283matched skills already investigate — long before this vulnerability was disclosed. Claude's reasoning model maps these techniques to MITRE ATT&CK, so practitioners who ran these skills have already seen the threat behaviour in their findings.

Analysis

The WP OAuth Server plugin contains a critical authentication bypass vulnerability where OpenID Connect identity assertions are not properly bound to specific authorization grants. Instead of validating that an assertion belongs to the user who initiated the authentication flow, the plugin returns the assertion for the most recently authenticated user. This allows any subscriber-level user to obtain valid identity assertions for other users—including administrators—and impersonate them in single sign-on (SSO) scenarios. Organizations relying on WordPress as an SSO provider face severe compromise risks, as attackers can escalate privileges and gain administrative access without knowing credentials.

Casky's 283 mapped skills detect the attack patterns underlying this vulnerability by analyzing MITRE techniques TA0004 (Privilege Escalation) and TA0006 (Credential Access). Practitioners using Casky would identify suspicious patterns such as identity assertion mismatches, authentication tokens issued to users different from the requester, and role elevation without legitimate authorization requests. The platform's extended reasoning capabilities flag anomalies in OpenID Connect token binding logic, cross-user session establishment, and SSO authentication flows where grant validation is bypassed. Security teams would see findings indicating unauthorized token generation, session hijacking indicators, and identity switching events—allowing them to detect exploitation attempts before attackers establish persistence in downstream SSO-integrated applications.

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Casky Risk Score

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EPSS Probability

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Shodan Exposure

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GreyNoise Signal

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Composite risk scoring from EPSS, CISA KEV, Shodan, and GreyNoise — 21 security APIs correlated into a single Casky Risk Score. Coming in Casky Pro. Join early access →

283 Casky skills cover this attack pattern

These skills use Claude AI's reasoning model to surface findings in the same attack categories as CVE-2026-82843.

abusing-dpapi-for-credential-access

red teaming · high

Run

abusing-shadow-credentials-for-privesc

red teaming · high

Run

Access with Stolen Session Cookie

identity access management · low

Run

MITRE ATT&CK Techniques

TA0004 TA0006

Investigate the attack patterns behind CVE-2026-82843

Casky has 283 skills that investigate the attack patterns behind CVE-2026-82843. Run one and get CVSS-scored findings in 3 minutes.

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