nicu_m Simple JWT Login Plugin up to 3.6.6 on WordPress auth payload injection

Summaryinfo

A vulnerability was found in nicu_m Simple JWT Login Plugin up to 3.6.6. It has been classified as critical. Affected is an unknown function of the file /wp-json/simple-jwt-login/v1/auth of the component Login. Performing a manipulation of the argument payload results in injection. This vulnerability is cataloged as CVE-2026-14262. It is possible to initiate the attack remotely. There is no exploit available.

Detailsinfo

A vulnerability classified as critical has been found in nicu_m Simple JWT Login Plugin up to 3.6.6. This affects an unknown code block of the file /wp-json/simple-jwt-login/v1/auth of the component Login. The manipulation of the argument payload with an unknown input leads to a injection vulnerability. CWE is classifying the issue as CWE-74. The product constructs all or part of a command, data structure, or record using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify how it is parsed or interpreted when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. The summary by CVE is:

The Simple JWT Login – Allows you to use JWT on REST endpoints. plugin for WordPress is vulnerable to Authentication Bypass to Privilege Escalation in all versions up to, and including, 3.6.6 via the `payload` parameter. The vulnerability exists because `AuthenticateService::generatePayload()` only overwrites JWT payload keys whose names appear in the admin-configured `jwt_payload` list — leaving any attacker-supplied identity claims such as `email`, `id`, or `username` intact and signed into the JWT with the site's HS256 secret. This makes it possible for authenticated attackers, with subscriber-level access and above, to escalate their privileges to that of an Administrator by injecting a target administrator's email address into the `payload` parameter at the `/wp-json/simple-jwt-login/v1/auth` endpoint, then redeeming the resulting JWT at the `/autologin` endpoint to obtain a fully authenticated session as that administrator.

It is possible to read the advisory at wordfence.com. This vulnerability is uniquely identified as CVE-2026-14262 since 06/30/2026. The exploitability is told to be easy. It is possible to initiate the attack remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 07/11/2026). The attack technique deployed by this issue is T1055 according to MITRE ATT&CK.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-43145). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• WordPress Plugin

Vendor

• nicu_m

Name

• Simple JWT Login Plugin

Version

• 3.6.0
• 3.6.1
• 3.6.2
• 3.6.3
• 3.6.4
• 3.6.5
• 3.6.6

CPE 2.3info

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CPE 2.2info

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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