Common Weakness Enumeration
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CWE-940
Improper Verification of Source of a Communication Channel
The product establishes a communication channel to handle an incoming request that has been initiated by an actor, but it does not properly verify that the request is coming from the expected origin.
CVE-2026-55660 (GCVE-0-2026-55660)
Vulnerability from cvelistv5 – Published: 2026-07-01 21:00 – Updated: 2026-07-02 12:43
VLAI
EPSS
VEX
Title
TinaCMS: Cross-origin postMessage handlers and rich-text URL-sanitization bypass enable stored XSS and session takeover
Summary
Tina is a headless content management system. In versions prior to @tinacms/app 2.5.6 and tinacms 3.9.3, cross-origin postMessage handlers and a rich-text URL-sanitization bypass enable stored XSS and session takeover. The library registers window message listeners — the useTina overlay handler, the OAuth authentication popup handler, and the admin↔preview iframe GraphQL reducer — that act on event.data without verifying event.origin or event.source and post messages using non-specific target origins, while insufficient URL sanitization in rich-text content allows malicious URLs to persist and execute. A page the victim visits (or a window in an opener/iframe relationship with a Tina admin) can forge messages to drive the editor, inject preview content, or observe/forge the OAuth popup channel to take over an authenticated editing session. This issue has been fixed in versions @tinacms/app 2.5.6 and tinacms 3.9.3.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: total
CISA Coordinator (v2.0.3)
CWE
Assigner
References
2 references
| URL | Tags |
|---|---|
| https://github.com/tinacms/tinacms/security/advis… | x_refsource_CONFIRM |
| https://github.com/tinacms/tinacms/pull/7056 | x_refsource_MISC |
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| tinacms | tinacms |
Affected:
< 3.9.3
|
|
| tinacms | @tinacms/app |
Affected:
< 2.5.6
|
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Mitigation
Phase: Architecture and Design
Description:
- Use a mechanism that can validate the identity of the source, such as a certificate, and validate the integrity of data to ensure that it cannot be modified in transit using an Adversary-in-the-Middle (AITM) attack.
- When designing functionality of actions in the URL scheme, consider whether the action should be accessible to all mobile applications, or if an allowlist of applications to interface with is appropriate.
CAPEC-500: WebView Injection
An adversary, through a previously installed malicious application, injects code into the context of a web page displayed by a WebView component. Through the injected code, an adversary is able to manipulate the DOM tree and cookies of the page, expose sensitive information, and can launch attacks against the web application from within the web page.
CAPEC-594: Traffic Injection
An adversary injects traffic into the target's network connection. The adversary is therefore able to degrade or disrupt the connection, and potentially modify the content. This is not a flooding attack, as the adversary is not focusing on exhausting resources. Instead, the adversary is crafting a specific input to affect the system in a particular way.
CAPEC-595: Connection Reset
In this attack pattern, an adversary injects a connection reset packet to one or both ends of a target's connection. The attacker is therefore able to have the target and/or the destination server sever the connection without having to directly filter the traffic between them.
CAPEC-596: TCP RST Injection
An adversary injects one or more TCP RST packets to a target after the target has made a HTTP GET request. The goal of this attack is to have the target and/or destination web server terminate the TCP connection.