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CVE-2026-41259

Mastodon: Insufficient verification of email addresses

Published: Apr 23, 2026Updated: Apr 28, 2026 Sources: CVE List NVD BDUCWE-841
7.5HIGH
NVD MITRE
EPSS Score
0.2%
Top 88.6%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available
Self-Check
Not available

Description

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.

No summary for this CVE yet.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:HA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:HIntegrity
High
A:NAvailability
None
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Weaknesses

CWE-841

Affected Products

joinmastodon
oss-projectaka mastodon
mastodonOn-prem
Communications / messaging-chat
mastodon
oss-projectaka mastodon/mastodon
mastodonOn-prem
Communications / messaging-chat
Mastodon gGmbH
oss-project·DEaka mastodon
MastodonMixed
Communications / messaging-chat

Exploitability

Official Patch Available
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References

https://github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhh
github.com
https://github.com/mastodon/mastodon/security/advisories/GHSA-5r37-qpwq-2jhh
github.com
https://github.com/mastodon/mastodon/releases/tag/v4.5.9
github.com
and 2 more references View all →

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