CVE-2026-46349 - Vulnerability Details - OpenCVE

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to re-arrange a valid signed JSON-LD activity from a third-party actor to have it processed differently. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Unchanged

Confidentiality Impact None

Integrity Impact Low

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploitation none

Automatable yes

Technical Impact partial

Vendors	Products
Joinmastodon	Mastodon

No data.

No data.

References

Link	Providers
https://github.com/mastodon/mastodon/security/advisories/GHSA-chgx-jx3p-rf73

History

Thu, 25 Jun 2026 14:30:00 +0000

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Thu, 25 Jun 2026 13:30:00 +0000

Type	Values Removed	Values Added
First Time appeared		Joinmastodon Joinmastodon mastodon
Vendors & Products		Joinmastodon Joinmastodon mastodon

Wed, 24 Jun 2026 20:00:00 +0000

Type	Values Removed	Values Added
Description		Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, Mastodon's normalization of incoming activities signed with Linked-Data Signatures does not sufficiently protect the activities from a certain class of spoofing, allowing attackers to re-arrange a valid signed JSON-LD activity from a third-party actor to have it processed differently. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.
Title		Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring
Weaknesses		CWE-347
References		https://github.com/mastodon/mastodon/security/advisories/GHSA-chgx-jx3p-rf73
Metrics		cvssV3_1 `{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N'}`

MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-06-24T19:40:35.022Z

Updated: 2026-06-25T13:16:49.851Z

Reserved: 2026-05-13T18:37:30.990Z

Link: CVE-2026-46349

Vulnrichment

Updated: 2026-06-25T13:16:46.452Z

NVD

No data.

Redhat

No data.

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