CVE-2025-62605

Unknown Unknown - Not Provided

BaseFortify

Publication date: 2025-10-21

Last updated on: 2025-12-12

Assigner: GitHub, Inc.

Description

Mastodon is a free, open-source social network server based on ActivityPub. In Mastodon version 4.4, support for verifiable quote posts with quote controls was added, but it is possible for an attacker to bypass these controls in Mastodon versions prior to 4.4.8 and 4.5.0-beta.2. Mastodon internally treats reblogs as statuses. Since they were not special-treated, an attacker could reblog any post, then quote their reblog, technically quoting themselves, but having the quote feature a preview of the post they did not get authorization for with all of the affordances that would be otherwise denied by the quote controls. This issue has been patched in versions 4.4.8 and 4.5.0-beta.2.

CVSS Scores

EPSS Scores

Probability:
Percentile:

Meta Information

Published

2025-10-21

Last Modified

2025-12-12

Generated

2026-07-06

AI Q&A

2025-10-21

EPSS Evaluated

2026-07-05

NVD

CVE-2025-62605

EUVD

EUVD-2025-35213

Affected Vendors & Products

Vendor	Product	Version / Range
joinmastodon	mastodon	From 4.4.0 (inc) to 4.4.8 (exc)
joinmastodon	mastodon	4.5.0

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-754	The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

Attack-Flow Graph

Executive Summary

This vulnerability in Mastodon versions prior to 4.4.8 and 4.5.0-beta.2 allows an attacker to bypass quote controls by reblogging any post and then quoting their own reblog. Since Mastodon treats reblogs as statuses without special handling, the attacker can quote themselves but display a preview of the original post they were not authorized to quote, circumventing the intended quote restrictions.

Impact Analysis

An attacker exploiting this vulnerability could display unauthorized previews of posts by bypassing quote controls, potentially exposing content that should be restricted or controlled. This could lead to unintended information disclosure or misuse of content within the Mastodon social network.

Mitigation Strategies

Upgrade Mastodon to version 4.4.8 or later, or to version 4.5.0-beta.2 or later, as these versions contain patches that fix the vulnerability allowing quote control bypass.

Hi! I’m here to help you understand CVE-2025-62605. Ask me anything about the vulnerability, its impact, or mitigation strategies.

0/70