Cyber Resilience

CVE-2026-85590

Public PoC
Published
04 September 2026
Modified
04 September 2026
CVSS Score v4 7.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0039 32th percentile
Risk Priority 36 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2026-85590 is a high-severity Use of Single-factor Authentication (CWE-308) vulnerability. Its CVSS base score is 7.1 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Password Spraying (T1110.003); ranked at the 32th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to IA-2 (Identification and Authentication (Organizational Users)) and IA-8 (Identification and Authentication (Non-organizational Users)) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A07:2025 Authentication Failures

EU & UK References

Vulnerability Data

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…

more

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.

CWE(s)
CWE-308

Related Threats

MITRE ATT&CK Enterprise Techniques

T1110.003 Password Spraying Credential Access
Adversaries may use a single or small list of commonly used passwords against many different accounts to attempt to acquire valid account credentials.
attack.mitre.org →
T1021 Remote Services Lateral Movement
Adversaries may use [Valid Accounts](https://attack.
attack.mitre.org →
T1078 Valid Accounts Stealth
Adversaries may obtain and abuse credentials of existing accounts as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1078.001 Default Accounts Stealth
Adversaries may obtain and abuse credentials of a default account as a means of gaining Initial Access, Persistence, Privilege Escalation, or Defense Evasion.
attack.mitre.org →
T1110 Brute Force Credential Access
Adversaries may use brute force techniques to gain access to accounts when passwords are unknown or when password hashes are obtained.
attack.mitre.org →
T1110.001 Password Guessing Credential Access
Adversaries with no prior knowledge of legitimate credentials within the system or environment may guess passwords to attempt access to accounts.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-34228Shared CWE-308
CVE-2023-49075Shared CWE-308
CVE-2026-15616Shared CWE-308
CVE-2023-25681Shared CWE-308
CVE-2024-27928Shared CWE-308
CVE-2026-67611Shared CWE-308
CVE-2026-56022Shared CWE-308
CVE-2024-50618Shared CWE-308
CVE-2024-47652Shared CWE-308
CVE-2025-42959Shared CWE-308

Affected Assets

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V6.3.4
  • V6.3.6
  • V6.4.2
  • V6.4.3

Mitigating Controls (NIST 800-53 r5) AI

IA-2 Identification and Authentication (Organizational Users) good match

ia-2 requires unique identification and authentication of users, directly stopping single-factor schemes by mandating appropriate (multi-factor) mechanisms.

IA-8 Identification and Authentication (Non-organizational Users) good match

ia-8 requires unique identification and authentication of non-organizational users, directly stopping single-factor schemes by mandating appropriate (multi-factor) mechanisms.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-03 full match
prevents

Explicit MFA requirement directly eliminates single-factor authentication while the control also addresses broader authentication scope.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.5 Secure authentication full match
degrades

Secure authentication control explicitly requires multi-factor authentication, directly eliminating single-factor weakness.

A.5.17 Authentication information mostly match
degrades

Authentication information control directly addresses the need for strong, multi-factor credentials.

A.5.15 Access control partial match
prevents

Access control policy can mandate multi-factor authentication but does not prescribe the technical implementation.

A.5.18 Access rights partial match
degrades

Access rights provisioning can require MFA, yet the control is broader than authentication strength.

A.8.2 Privileged access rights partial match
degrades

Privileged access rights can be conditioned on MFA, but the control focuses on privilege scope rather than factor count.

A.8.3 Information access restriction partial match
degrades

Information access restriction can enforce MFA, yet the control is wider than authentication mechanisms.

References