CVE Tools
Sign in

CVE-2026-22245

Mastodon has SSRF Protection bypass

Published: Jan 8, 2026Updated: Jan 15, 2026 Sources: CVE List NVDCWE-918
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.2%
Top 84.4%
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. By nature, Mastodon performs a lot of outbound requests to user-provided domains. Mastodon, however, has some protection mechanism to disallow requests to local IP addresses (unless specified in `ALLOWED_PRIVATE_ADDRESSES`) to avoid the "confused deputy" problem. The list of disallowed IP address ranges was lacking some IP address ranges that can be used to reach local IP addresses. An attacker can use an IP address in the affected ranges to make Mastodon perform HTTP requests against loopback or local network hosts, potentially allowing access to otherwise private resources and services. This is fixed in Mastodon v4.5.4, v4.4.11, v4.3.17 and v4.2.29.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:HI:NA:N
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:HConfidentiality
High
I:NIntegrity
None
A:NAvailability
None
Open in CVSS calculator →

Weaknesses

CWE-918

Affected Products

mastodonjoinmastodon
On-prem
Communications / messaging-chat
mastodonmastodon
On-prem
Communications / messaging-chat
joinmastodonoss-projectCommunicationsaka mastodon
mastodonoss-projectCommunicationsaka mastodon/mastodon

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

Official Patch Available

MITRE ATT&CK

2 techniques
Command and Control
Initial Access
View detailed technique mapping

References

https://github.com/mastodon/mastodon/commit/0f4e8a6240b5af1f2c3f34d2793d8610c6ef2aca
github.com
https://github.com/mastodon/mastodon/commit/17022907866710a72a1b1fc0a5ce9538bad1b4c3
github.com
https://github.com/mastodon/mastodon/commit/71ae4cf2cf5138ccdda64b1b1d665849b688686d
github.com
and 1 more references View all →

Timeline

Published
Jan 8, 2026
Last Updated
Jan 15, 2026

Unlock Complete Vulnerability Intelligence

Get the full picture for CVE-2026-22245 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