phpMyFAQ: Use of Single-factor Authentication
CVE-2026-85590 is a high-severity use of single-factor authentication vulnerability in phpMyFAQ from Thorsten, with a CVSS 4.0 base score of 7.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. The record lists version 4.1.8 as the first without the flaw, so updating phpMyFAQ to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.52% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update phpMyFAQ to 4.1.8 or a later version.
- Read the advisory on github.com for workarounds and exact fixed builds.
Affected products and versions
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Attack requirements
- NoneThe attack does not depend on a particular deployment or configuration.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Confidentiality (vulnerable system)
- NoneNo loss of confidentiality on the vulnerable system.
- Integrity (vulnerable system)
- HighSerious loss of integrity on the vulnerable system.
- Availability (vulnerable system)
- NoneNo loss of availability on the vulnerable system.
- Confidentiality (other systems)
- NoneNo loss of confidentiality on systems beyond the vulnerable one.
- Integrity (other systems)
- NoneNo loss of integrity on systems beyond the vulnerable one.
- Availability (other systems)
- NoneNo loss of availability on systems beyond the vulnerable one.
Vector: 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/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. Scored by CNA (vulncheck.com).
Official 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: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use of Single-factor Authentication
The product uses an authentication algorithm that uses a single factor (e.g., a password) in a security context that should require more than one factor.
How developers prevent this class of flaw
- Use multiple independent authentication schemes, which ensures that -- if one of the methods is compromised -- the system itself is still likely safe from compromise. For this reason, if multiple schemes are possible, they should be implemented and required -- especially if they are easy to use.
More Use of Single-factor Authentication vulnerabilities (CWE-308)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other references
Other vulnerabilities in phpMyFAQ
- 7.3 High severity
- 7.5 High severity
- 9.8 Critical severity
- 8.1 High severity
- 8.3 High severity
- 7.1 High severity
Recent Use of Single-factor Authentication vulnerabilities
- 8.1 High severity
- 9.1 Critical severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 7.2 High severity
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