CVE Alert: CVE-2025-46340
Vulnerability Summary: CVE-2025-46340
Misskey is an open source, federated social media platform. Starting in version 12.0.0 and prior to version 2025.4.1, due to an oversight in the validation performed in `UrlPreviewService` and `MkUrlPreview`, it is possible for an attacker to inject arbitrary CSS into the `MkUrlPreview` component. `UrlPreviewService.wrap` falls back to returning the original URL if it’s using a protocol that is likely to not be understood by Misskey, IE something other than `http` or `https`. This both can de-anonymize users and_allow further attacks in the client. Additionally, `MkUrlPreview` doesn’t escape CSS when applying a `background-image` property, allowing an attacker to craft a URL that applies arbitrary styles to the preview element. Theoretically, an attacker can craft a CSS injection payload to create a fake error message that can deceive the user into giving away their credentials or similar sensitive information. Version 2025.4.1 contains a patch for the issue.
Affected Endpoints:
No affected endpoints listed.
Published Date:
5/5/2025, 7:15:56 PM
🔥 CVSS Score:
Exploit Status:
Not ExploitedReferences:
- https://github.com/misskey-dev/misskey/commit/d10fdfe9738b17a9d81037c031b40a2cc4cb8038
- https://github.com/misskey-dev/misskey/security/advisories/GHSA-3p2w-xmv5-jm95
Recommended Action:
No proposed action available. Please refer to vendor documentation for updates.
A considerable amount of time and effort goes into maintaining this website, creating backend automation and creating new features and content for you to make actionable intelligence decisions. Everyone that supports the site helps enable new functionality.
If you like the site, please support us on “Patreon” or “Buy Me A Coffee” using the buttons below
To keep up to date follow us on the below channels.
