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CVE-2026-85590— phpMyFAQ before 4.1.8 Authentication Bypass via Two-Factor Disable

Quick assessment

Affected
thorsten phpMyFAQ
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

phpMyFAQ 在 4.1.8 之前版本中存在一个认证绕过漏洞，影响其双因素认证（TOTP）的禁用功能。 处理器（可通过 POST 访问）仅验证用户是否已登录以及是否提供了有效的 CSRF token，随后即可禁用 TOTP，而不要求重新输入密码或当前的 TOTP 验证码。同样的降级操作也可以通过 PUT 内联实现，该接口在相同的“会话 + CSRF”防护下，接受一个普通的 表单字段。 攻击者若能劫持某个用户的会话，就可以悄无声息地移除任何账户（包括管理员账户）的双因素保护。一旦双因素保护被移除，仅凭密码即可成功

CVSS 7.1 · High

Possible ATT&CK Techniques 1 AI

T1557.004 · Evil Twin

Affected Version Matrix 2

VendorProduct Version RangeStatus
thorsten phpMyFAQ < 4.1.8 affected
4.1.8 unaffected
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I. Basic Information for CVE-2026-85590

Vulnerability Information
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Vulnerability Title
phpMyFAQ before 4.1.8 Authentication Bypass via Two-Factor Disable
Source: CVE Program / CVE List V5
Vulnerability Description
phpMyFAQ before 4.1.8 contains an authentication bypass vulnerability in its two-factor authentication (TOTP) disable functionality. The removeTwofactorConfig() handler (reachable via POST /api/user/remove-twofactor) verifies only that the user is logged in and that a valid CSRF token is supplied, then disables TOTP without requiring password re-entry or a current TOTP code. The same downgrade is also reachable inline via PUT /api/user/data/update, which accepts a plain twofactor_enabled form field under the same session+CSRF-only guard. An attacker who has hijacked a user's session can silently strip two-factor protection from any account, including administrator accounts, after which password-only authentication succeeds.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
使用单一因素认证机制
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
thorsten phpMyFAQ 0 ~ 4.1.8 -

II. Public POCs for CVE-2026-85590

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III. Intelligence Information for CVE-2026-85590

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Vendor Advisories for CVE-2026-85590 (2)

Same Patch Batch · thorsten · 2026-09-04 · 8 CVEs total

CVE-2026-85591 7.1 HIGH phpMyFAQ before 4.1.8 Authentication Bypass via Unverified Password Change
CVE-2026-85586 6.9 MEDIUM phpMyFAQ before 4.1.8 CAPTCHA Bypass via store parameter
CVE-2026-85593 5.4 MEDIUM phpMyFAQ before 4.1.8 Stored XSS via html_entity_decode
CVE-2026-85587 5.3 MEDIUM phpMyFAQ before 4.1.8 Incorrect Authorization via Admin Pages
CVE-2026-85588 5.3 MEDIUM phpMyFAQ before 4.1.8 TOTP Secret Exposure via Data Export
CVE-2026-85589 5.3 MEDIUM phpMyFAQ before 4.2.0-alpha.2 Missing Authorization via Dashboard API
CVE-2026-85592 3.7 LOW phpMyFAQ before 4.1.8 Authorization Bypass via question/create

IV. Related Vulnerabilities

Same product: phpMyFAQ
Same vendor: thorsten
Same weakness: CWE-308

V. Comments for CVE-2026-85590

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