CVE-2026-22246
Jan. 8, 2026, 6:08 p.m.
6.5
Medium
Description
Mastodon is a free, open-source social network server based on ActivityPub. Mastodon 4.3 added notifications of severed relationships, allowing end-users to inspect the relationships they lost as the result of a moderation action. The code allowing users to download lists of severed relationships for a particular event fails to check the owner of the list before returning the lost relationships. Any registered local user can access the list of lost followers and followed users caused by any severance event, and go through all severance events this way. The leaked information does not include the name of the account which has lost follows and followers. This has been fixed in Mastodon v4.3.17, v4.4.11 and v4.5.4.
Product(s) Impacted
| Vendor | Product | Versions |
|---|---|---|
| Mastodon |
|
|
Weaknesses
Common security weaknesses mapped to this vulnerability.
CWE-201
Insertion of Sensitive Information Into Sent Data
The code transmits data to another actor, but a portion of the data includes sensitive information that should not be accessible to that actor.
*CPE(s)
Affected systems and software identified for this CVE.
| Type | Vendor | Product | Version | Update | Edition | Language | Software Edition | Target Software | Target Hardware | Other Information |
|---|---|---|---|---|---|---|---|---|---|---|
| a | mastodon | matodon | 4.3 | / | / | / | / | / | / | / |
| a | mastodon | matodon | <4.3.17 | / | / | / | / | / | / | / |
| a | mastodon | matodon | 4.4.11 | / | / | / | / | / | / | / |
| a | mastodon | matodon | 4.5.4 | / | / | / | / | / | / | / |
References
Tags
CVSS Score
CVSS Data - 3.1
- Attack Vector: NETWORK
- Attack Complexity: LOW
- Privileges Required: LOW
- Scope: UNCHANGED
- Confidentiality Impact: HIGH
- Integrity Impact: NONE
- Availability Impact: NONE
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Timeline
Published: Jan. 8, 2026, 4:16 p.m.
Last Modified: Jan. 8, 2026, 6:08 p.m.
Last Modified: Jan. 8, 2026, 6:08 p.m.
Status : Awaiting Analysis
CVE has been recently published to the CVE List and has been received by the NVD.
More infoSource
security-advisories@github.com
*Disclaimer: Some vulnerabilities do not have an associated CPE. To enhance the data, we use AI to infer CPEs based on CVE details. This is an automated process and might not always be accurate.