CVE-2026-46349 — Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring

CVE-2026-46349

Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring PUBLISHED

Description (CNA)

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.

Affected (CNA)

Vendor / product	Versions
mastodon / mastodon	affected >= 4.5.0-beta.1, < 4.5.10

CWE

CWE-347

References

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

ADP enrichment

CISA-ADP

No English description supplied.

No references supplied.