CVE-2026-46349
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…
Does this matter?
Lower severity and a low EPSS score (0.19%). Track it; it rarely justifies an emergency change on its own.
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.
- CVSS 3.1
- 5.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- EPSS
- 0.19% probability · 9th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-347
- Source
- security-advisories@github.com
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.