CVE-2026-28355 "PWA" Canarytoken Vulnerable to Stored Self Cross-Site Scripting

What is CVE-2026-28355?

CVE-2026-28355 is a low-severity cross-site scripting vulnerability in thinkst canarytokens, published on 27 Feb 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official description

Canarytokens help track activity and actions on a network. Versions prior to `sha-7ff0e12` have a Self Cross-Site Scripting vulnerability in the "PWA" Canarytoken, whereby the Canarytoken's creator can attack themselves or someone they share the link with. The creator of a PWA Canarytoken can insert Javascript into the title field of their PWA token. When the creator later browses the installation page for their own Canarytoken, the Javascript executes. This is a self-XSS. An attacker could create a Canarytoken with this self-XSS, and send the install link to a victim. When they click on it, the Javascript would execute. However, no sensitive information (ex. session information) will be disclosed to the malicious actor. This issue is now patched on Canarytokens.org. Users of self-hosted Canarytokens installations can update by pulling the latest Docker image, or any Docker image after sha-7ff0e12.

Weakness: CWE-79

Which versions are affected by CVE-2026-28355?

How do I fix CVE-2026-28355?

No fix has been published for CVE-2026-28355 yet. Limit exposure of the affected software until one is available.

Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.

Is CVE-2026-28355 being exploited?

There is no known exploitation of CVE-2026-28355 in the wild and no public exploit code.

Sources

• CVE record
• NVD
• OSV
• How this page is made