Description
Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was lacking an IP address range that can be used to reach local IP addresses. An attacker can use an IP address in the affected range to make Mastodon perform HTTP requests against loopback interfaces, potentially allowing access to otherwise private resources and services. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.
Published: 2026-06-24
Score: 8.7 High
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Analysis and contextual insights are available on OpenCVE Cloud.

Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Thu, 25 Jun 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Thu, 25 Jun 2026 13:30:00 +0000

Type Values Removed Values Added
First Time appeared Joinmastodon
Joinmastodon mastodon
Vendors & Products Joinmastodon
Joinmastodon mastodon

Wed, 24 Jun 2026 20:00:00 +0000

Type Values Removed Values Added
Description Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.5.10, 4.4.17, and 4.3.23, the list of disallowed IP address ranges was lacking an IP address range that can be used to reach local IP addresses. An attacker can use an IP address in the affected range to make Mastodon perform HTTP requests against loopback interfaces, potentially allowing access to otherwise private resources and services. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.
Title Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)
Weaknesses CWE-918
References
Metrics cvssV4_0

{'score': 8.7, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N'}


Subscriptions

Joinmastodon Mastodon
cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-06-25T17:11:24.737Z

Reserved: 2026-05-13T18:37:30.990Z

Link: CVE-2026-46348

cve-icon Vulnrichment

Updated: 2026-06-25T17:11:20.693Z

cve-icon NVD

No data.

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-25T13:15:03Z

Weaknesses