WPCOM Member <= 1.7.27 - Unauthenticated Authentication Bypass via 'uuid' and 'code' Parameters on Social-Login Callback

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-104803
StatePUBLISHED
AssignerWordfence
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-10-10 08:17:04 UTC
Updated2026-10-11 17:17:00 UTC
DescriptionThe WPCOM Member plugin for WordPress is vulnerable to Authentication Bypass in all versions up to, and including, 1.7.27 via the `uuid` and `code` parameters of the social-login callback handler registered on the `init` hook. The vulnerability exists because the `login` function's social-login flow performs no nonce validation, no OAuth state verification, and no per-visitor namespace isolation in the session store, allowing an unauthenticated attacker to issue a crafted GET request that writes an attacker-named, attacker-valued entry into the global session namespace (bypassing the per-visitor prefix by prepending an underscore), then issue a second GET request triggering `weapp_new_user()` to read that forged entry and resolve the attacker-supplied `openid` value to a bound WordPress account before `wp_set_auth_cookie()` establishes a fully authenticated session. This makes it possible for unauthenticated attackers to log in as any WordPress user — including administrators — whose bound social provider identifier (openid/unionid) is known or discoverable. Successful exploitation requires that the target site has at least one social provider configured (which activates the vulnerable handler) and that the attacker knows or can enumerate the victim account's bound openid or unionid.

Risk And Classification

Primary CVSS: v3.1 9.8 CRITICAL from [email protected]

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

EPSS: 0.004490000 probability, percentile 0.371580000 (date 2026-10-11)

Problem Types: CWE-287 | CWE-287 CWE-287 Improper Authentication

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED9.8CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Whyun WPCOM Member affected 1.7.27 semver Not specified

References

ReferenceSourceLinkTags
www.wordfence.com/threat-intel/vulnerabilities/id/3dee7f76-bd66-4e54-8ef6-bbf58... [email protected] www.wordfence.com
plugins.trac.wordpress.org/browser/wpcom-member/tags/1.7.27/includes/social-login.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/wpcom-member/trunk/includes/social-login.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/wpcom-member/tags/1.7.27/includes/social-login.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/wpcom-member/tags/1.7.27/includes/social-login.php [email protected] plugins.trac.wordpress.org
plugins.trac.wordpress.org/browser/wpcom-member/tags/1.7.27/includes/class-sesstion.php [email protected] plugins.trac.wordpress.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Mohamed Khater (en)

Additional Advisory Data

SourceTimeEvent
CNA2026-10-02T13:35:49.000ZVendor Notified
CNA2026-10-09T19:08:23.000ZDisclosed

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