BaseFortify

Publication date: 2025-10-13

Last updated on: 2025-10-20

Assigner: GitHub, Inc.

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2025-10-13

Last Modified

2025-10-20

Generated

2026-07-06

AI Q&A

2025-10-14

EPSS Evaluated

2026-07-05

NVD

CVE-2025-62176

Affected Vendors & Products

Vendor	Product	Version / Range
joinmastodon	mastodon	to 4.2.27 (exc)
joinmastodon	mastodon	From 4.3.0 (inc) to 4.3.14 (exc)
joinmastodon	mastodon	From 4.4.0 (inc) to 4.4.6 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-280	The product does not handle or incorrectly handles when it has insufficient privileges to access resources or functionality as specified by their permissions. This may cause it to follow unexpected code paths that may leave the product in an invalid state.

Attack-Flow Graph

Impact Analysis

The impact is limited because it only affects new public posts published on the public timelines and requires an otherwise valid authentication token. However, it may lead to unexpected access to public posts by OAuth clients that should not have read permissions, which could expose information in a limited-federation environment.

Mitigation Strategies

Upgrade Mastodon to version 4.4.6, 4.3.14, or 4.2.27 or later, as these versions contain the patch that fixes this vulnerability. No known workarounds exist.

Executive Summary

This vulnerability in Mastodon before versions 4.4.6, 4.3.14, and 4.2.27 allows the streaming server to serve events for public timelines to clients using any valid authentication token, even if those tokens do not have the read:statuses scope. This means OAuth clients without the proper read permissions can still subscribe to public channels and receive public timeline events, potentially leading to unexpected access to public posts in limited-federation settings.

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