VulnerabilityPublished 27 Feb 2026Updated 3 Mar 2026

CVE-2026-27836: thorsten phpMyFAQ · Missing Authorization

Affects thorsten phpMyFAQSource CVE Database V5

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Not known to be exploited · CVSS 7.5 High : upgrade to 4.0.18 soon.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 3.1 base score

7.5High

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 39% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 4.0.18

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: None: There is no loss of confidentiality within the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 27 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade phpMyFAQ and thorsten/phpMyFAQ to 4.0.18.

Affected software

Product	Affected	Fixed in
thorstenphpMyFAQ	Affected <4.0.18	Fixed in 4.0.18
GitHubthorsten/phpMyFAQ`pkg:github/thorsten/phpMyFAQ`Other threats	Affected <4.0.18	Fixed in 4.0.18

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

The most effective mitigation is to upgrade phpMyFAQ installations to version 4.0.18 or later, where the vulnerability is patched with proper authorization checks on the WebAuthn prepare endpoint. Until upgrading is possible, organizations should implement strict network-level access controls to restrict access to the vulnerable endpoint, such as IP whitelisting or web application firewall (WAF) rules that block unauthenticated requests to `/api/webauthn/prepare`. Monitoring and alerting on unusual account creation patterns can help detect exploitation attempts early. Disabling WebAuthn features if not in use can reduce the attack surface. Additionally, applying rate limiting on account creation endpoints can mitigate abuse. Reviewing and tightening user role assignments and permissions can limit the impact of unauthorized accounts. Finally, organizations should ensure that registration is properly disabled in configuration settings and verify that no other endpoints suffer from similar missing authorization issues.

Description

phpMyFAQ is an open source FAQ web application. Prior to version 4.0.18, the WebAuthn prepare endpoint (`/api/webauthn/prepare`) creates new active user accounts without any authentication, CSRF protection, captcha, or configuration checks. This allows unauthenticated attackers to create unlimited user accounts even when registration is disabled. Version 4.0.18 fixes the issue.

Impact

The primary impact of CVE-2026-27836 is on the integrity of phpMyFAQ installations, as unauthorized attackers can create unlimited active user accounts without authentication. This undermines trust in the user management system and can lead to several downstream risks, including privilege escalation if attackers manage to gain elevated roles via created accounts or exploit other vulnerabilities. The lack of registration restrictions can also result in spam accounts, cluttering the system and potentially degrading performance. Although confidentiality and availability are not directly affected, the integrity compromise can facilitate further attacks that may impact these areas. Organizations relying on phpMyFAQ for customer support, knowledge bases, or internal documentation may face operational disruptions and reputational damage if attackers abuse this vulnerability. The vulnerability’s remote and unauthenticated exploitability increases the risk of widespread abuse, especially in environments where phpMyFAQ is exposed to the internet. The absence of known exploits in the wild suggests limited current exploitation but does not preclude future attacks, particularly as details become more widely known.

CWE-862Missing Authorization (opens in a new tab)
Class weaknessLikelihood of exploit: HighCWE Top 25 (2025): #4OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
Architecture and Design
Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) to enforce the roles at the appropriate boundaries.
Architecture and Design
Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records.
Architecture and Design · Libraries or Frameworks
Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
OWASP Cheat Sheets
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V8.3.8 (opens in a new tab)
V13.4.2 (opens in a new tab)
V7.2.2 (opens in a new tab)
Attack patterns
Exploitation of Thunderbolt Protection Flaws (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 6 Mar 2026, 21:18 UTC

WeaknessesCWE-862

Technical details

References

Community reviews

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