CVE-2026-41259
Published:April 23, 2026
Updated:April 26, 2026
Mastodon is a free, open-source social network server based on ActivityPub. Prior to v4.5.9, v4.4.16, and v4.3.22, Mastodon allows restricting new user sign-up based on e-mail domain names, and performs basic validation on e-mail addresses, but fails to restrict characters that are interpreted differently by some mailing servers. This vulnerability is fixed in v4.5.9, v4.4.16, and v4.3.22.
Affected Packages
https://github.com/mastodon/mastodon.git (GITHUB):
Affected version(s) >=v4.4.0 <v4.4.16Fix Suggestion:
Update to version v4.4.16https://github.com/mastodon/mastodon.git (GITHUB):
Affected version(s) >=v4.5.0 <v4.5.9Fix Suggestion:
Update to version v4.5.9https://github.com/mastodon/mastodon.git (GITHUB):
Affected version(s) >=v0.1.0 <v4.3.22Fix Suggestion:
Update to version v4.3.22Related Resources (1)
Do you need more information?
Contact UsCVSS v4
Base Score:
8.2
Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
Vulnerable System Confidentiality
NONE
Vulnerable System Integrity
HIGH
Vulnerable System Availability
NONE
Subsequent System Confidentiality
NONE
Subsequent System Integrity
NONE
Subsequent System Availability
NONE
CVSS v3
Base Score:
7.5
Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Weakness Type (CWE)
Improper Enforcement of Behavioral Workflow
