CVE-2026-28355
Self-XSS Vulnerability in Canarytokens PWA Installation Page
Publication date: 2026-02-27
Last updated on: 2026-02-27
Assigner: GitHub, Inc.
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| thinkst | canarytokens | to sha-7ff0e12 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-79 | The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
[{'type': 'paragraph', 'content': 'CVE-2026-28355 is a Stored Self Cross-Site Scripting (Self-XSS) vulnerability in the "PWA" Canarytoken component of the Canarytokens project. The vulnerability arises because the title field of a PWA Canarytoken allows the token creator to insert arbitrary JavaScript code. When the creator later visits the installation page of their own Canarytoken, the injected JavaScript executes in their browser context.'}, {'type': 'paragraph', 'content': 'An attacker can craft a Canarytoken containing malicious JavaScript and send the installation link to a victim, causing the script to execute when the victim opens the link. However, no sensitive information such as session data is disclosed to the attacker.'}, {'type': 'paragraph', 'content': 'This vulnerability is classified under CWE-79 due to improper sanitization of user input before rendering it in a web page. It affects versions prior to commit sha-7ff0e12 and has been patched in that commit.'}] [1]
How can this vulnerability impact me? :
[{'type': 'paragraph', 'content': 'This vulnerability allows the creator of a PWA Canarytoken to execute arbitrary JavaScript code in their own browser when viewing the installation page, which is a self-XSS scenario.'}, {'type': 'paragraph', 'content': "Additionally, an attacker could send a malicious Canarytoken installation link to a victim, causing the injected JavaScript to execute in the victim's browser when they open the link."}, {'type': 'paragraph', 'content': 'Despite this, the impact is limited because no sensitive information such as session data is disclosed to the attacker, and the overall severity is rated low.'}] [1]
How does this vulnerability affect compliance with common standards and regulations (like GDPR, HIPAA)?:
I don't know
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability is a Stored Self Cross-Site Scripting (Self-XSS) in the title field of the PWA Canarytoken. Detection involves identifying Canarytokens with injected JavaScript in the title field.
Since the vulnerability manifests when the token creator visits the installation page, monitoring for unusual JavaScript execution in the browser context of the token creator can help detect exploitation.
For self-hosted installations, you can check the version of your Canarytokens Docker image to see if it is prior to the patched commit sha-7ff0e12.
- Run the command to check your current Docker image version: `docker images thinkst/canarytokens`
- Look for any Canarytoken PWA titles containing suspicious JavaScript code by inspecting the token creation inputs or stored token data.
What immediate steps should I take to mitigate this vulnerability?
To mitigate this vulnerability, update your Canarytokens installation to a version that includes the patch after commit sha-7ff0e12.
For self-hosted Canarytokens installations, pull the latest Docker image with the following command:
- `docker pull thinkst/canarytokens:latest`
Avoid creating or sharing Canarytokens with untrusted JavaScript in the title field to prevent self-XSS attacks.