CVE Watchtower

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CVE-2026-54239NVD

Description

Faust.js is a headless WordPress toolkit. Prior to 1.8.11, the FaustWP WordPress plugin authenticates only the ciphertext in its token envelope and excludes the 16-byte initialization vector from the HMAC in WPE\FaustWP\Auth\encrypt() and WPE\FaustWP\Auth\decrypt() in plugins/faustwp/includes/auth/functions.php. A logged-in non-administrator who obtains an authorization code from GET /generate can modify the unauthenticated initialization vector so that CBC decryption changes the token type and user identifier while the HMAC remains valid. This can produce an access token for an Administrator and permit full WordPress REST API access, administrator-account creation, plugin installation, and arbitrary code execution. This issue is fixed in repository version 1.8.11.
Severity Level
HIGH (8.8)
Published Date
17/09/2026
Last Modified
18/09/2026
Exploitation Status
????
EPSS Score
0.21% (percentile 11.3%)

CVSS Base Metrics

CVSS v3 (3.1)
HIGH 8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Weaknesses (CWE)

CWE-345 - CWE-345: Insufficient Verification of Data AuthenticityCWE-639 - CWE-639: Authorization Bypass Through User-Controlled Key

Affected & Patched Versions

ProductAffected VersionsPatched Version
wpengine faustjs< 1.8.11N/A
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📧Email Delivery — Threat intel straight to your inbox.
♾️Unlimited Vendors — Track your entire stack.
🚨All New CVEs — Be the first to know.
⚙️Custom EPSS — Filter noise, focus on risk.
💬Webhooks — Slack & Teams integration.
🚫Ad-Free — Uninterrupted experience.