CVE Tools
Sign in

CVE-2026-41259

Mastodon: Insufficient verification of email addresses

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

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
Open in CVSS calculator →

Weaknesses

CWE-841

Affected Products

mastodonmastodon
On-prem
Communications / messaging-chat
mastodonjoinmastodon
On-prem
Communications / messaging-chat
MastodonMastodon gGmbH
Mixed
Communications / messaging-chat
mastodonoss-projectCommunicationsaka mastodon/mastodon
joinmastodonoss-projectCommunicationsaka mastodon
mastodon ggmbhoss-projectDECommunicationsaka mastodon

Exploitability

Official Patch Available

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 →

Timeline

Published
Apr 23, 2026
Last Updated
Apr 28, 2026

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-41259 and every CVE in our database. Create a free account — no credit card required.

Create Free Account
Plain-language analysis
Impact assessment and exploitation scenario in plain English
Attack graph visualization
Interactive attack path and kill chain mapping
Exploit details & PoC links
ExploitDB, Metasploit, GitHub PoCs with direct links
Nuclei scanner templates
Ready-to-use vulnerability scanner templates
Full remediation guide
Patch instructions, workarounds, and compliance impact
Interactive AI chat
Ask questions about this vulnerability in natural language
Related vulnerabilities
Semantically similar CVEs and attack patterns
REST API & MCP access
Integrate vulnerability data into your workflows