Mastodon: LD-Signature Bypass via JSON-LD Named-Graph Restructuring
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.
Problem Types
| Type | CWE ID | Description |
|---|
| CWE | CWE-347 | CWE-347: Improper Verification of Cryptographic Signature |
Type: CWE
Description: CWE-347: Improper Verification of Cryptographic Signature
Metrics
| Version | Base score | Base severity | Vector |
|---|
| 3.1 | 5.3 | MEDIUM | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |
Version: 3.1
Base score: 5.3
Base severity: MEDIUM
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N