Outbound Request Vulnerability in Mastodon Social Network Server
CVE-2026-22245

7.1HIGH

Key Information:

Vendor

Mastodon

Status
Mastodon
Vendor
CVE Published:
8 January 2026

What is CVE-2026-22245?

Mastodon, an open-source social networking server, faces an outbound request vulnerability that allows an attacker to leverage improperly restricted IP address ranges. This flaw enables unauthorized requests to local network hosts, potentially exposing sensitive internal services. By exploiting this, attackers can bypass Mastodon's existing protections against local IP access, urging users to update to secure versions to mitigate risks associated with this vulnerability.

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Affected Version(s)

mastodon < 4.2.29 < 4.2.29

mastodon >= 4.3.0-beta.1, < 4.3.17 < 4.3.0-beta.1, 4.3.17

mastodon >= 4.4.0-beta.1, < 4.4.11 < 4.4.0-beta.1, 4.4.11

References

https://github.com/mastodon/mastodon/security/advisories/...
x_refsource_CONFIRM
https://github.com/mastodon/mastodon/commit/0f4e8a6240b5a...
x_refsource_MISC
https://github.com/mastodon/mastodon/commit/1702290786671...
x_refsource_MISC

CVSS V4

Score:
7.1
Severity:
HIGH
Confidentiality:
None
Integrity:
High
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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