CVE-2026-82843

OAuth Server <= 6.3.0 - Authenticated (Subscriber+) Arbitrary User Identity Token Issuance to Privilege Escalation

2026-09-21 00:00

Strategic Overview

Status: Patched in 6.4.0
Affected Plugin: WP OAuth Server ( Login with WordPress )
Affected Version: <= 6.3.0
CVSS: 8.8High
Weakness type: CWE-287 · Improper Authentication
CVE: CVE-2026-82843

View all WP OAuth Server ( Login with WordPress ) vulnerabilities

At a glance

CVE-2026-82843 is a high-severity Improper Authentication vulnerability in the WP OAuth Server ( Login with WordPress ) WordPress plugin, affecting versions <= 6.3.0. It carries a CVSS score of 8.8 (reachable over the network; low attack complexity; high confidentiality, integrity, availability impact). Exploitation requires an authenticated account at Subscriber level or above. The issue is fixed in version 6.4.0; sites on affected versions should update now. Disclosed September 2026, reported by vuxvinh.

Vulnerability Overview

The WP OAuth Server ( Login with WordPress ) plugin for WordPress is vulnerable to Privilege Escalation in all versions up to, and including, 6.3.0. This makes it possible for authenticated attackers, with Subscriber-level access and above, to log in as other users without a password, including administrators.

Technical Analysis

The vector marks this flaw as remotely reachable over the network, with low attack complexity — no special timing or configuration is needed, and no interaction from a victim user. A successful exploit has high impact on confidentiality, integrity, availability — full site compromise territory.

CWE-287: Improper Authentication

Reaching this weakness in WP OAuth Server ( Login with WordPress ) <= 6.3.0 takes an account at Subscriber level or above. Improper authentication means the mechanism that proves who a caller is can be satisfied without the secret it was supposed to require.

An attacker authenticates as another user — administrators included — without ever knowing a password, so password policies and login rate limits never come into play. For WP OAuth Server ( Login with WordPress ) the fix is 6.4.0: builds <= 6.3.0 are affected, anything from 6.4.0 onward is not.

Remediation

Update to version 6.4.0, or a newer patched version

How does WordSec protect against this?

Because it turns on account access, WordSec's login security is the relevant layer: role-based two-factor, captcha and brute-force limits raise the cost of getting the account this needs. None of that substitutes for the fix: WP OAuth Server ( Login with WordPress ) 6.4.0 closes this, and updating the plugin is the step that ends it.

Login Security
Alerts

External References

https://www.cve.org/CVERecord?id=CVE-2026-82843 https://www.wordfence.com/threat-intel/vulnerabilities/id/0e1fb4b5-7020-4228-8831-324bbf748c51 https://nvd.nist.gov/vuln/detail/CVE-2026-82843

Related records

Other vulnerabilities in WP OAuth Server ( Login with WordPress )

CVSS Vector

8.8

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Base

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredLow
User InteractionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

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