Authentication Bypass in WPCOM Member (WordPress plugin) (CVE-2026-104803)
Summary
Authentication bypass in WPCOM Member (WordPress plugin) (CVE-2026-104803). Successful exploitation can lead to full system takeover. Exploitable via uuid.
Original description
The description as published by the source.
The 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.
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-104803 has been found in WPCOM Member (WordPress plugin).
Attackers can target a specific entry point like uuid over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: 9.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "WPCOM Member (WordPress plugin) CVE-2026-104803" on the vendor's site.
CVE-2026-104803 (WPCOM Member (WordPress plugin)) — CWE-287 / CVSS v3 9.8
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: uuid / code / init / login
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Authentication bypass (CWE-287) exists in WPCOM Member (WordPress plugin). Attackers reach the vulnerable code path via uuid without authentication.
Check the vendor advisory for the affected versions of WPCOM Member (WordPress plugin). Attack surface: uuid / code / init / login.
Severity: Critical (CVSS 9.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで WPCOM Member (WordPress plugin) を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
References
- web security@wordfence.com
- web security@wordfence.com
- web security@wordfence.com
- web security@wordfence.com
- web security@wordfence.com
- web security@wordfence.com
- web nvd.nist.gov
- web github.com