Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)_CVE-2026-46348

8.7 / 10

HIGH

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

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.

AI Analysis

SSRF Bypass via IPv6 Unspecified Address (::) in Mastodon prior to 4.5.10, 4.4.17, and 4.3.23

Basic Information

ID CVE-2026-46348

Source GitHub_M

Published Jun 24, 2026 at 19:39

Affected Product

Vendor mastodon

Product mastodon

Version >= 4.5.0-beta.1, < 4.5.10

Affected Versions mastodon mastodon >= 4.5.0-beta.1, < 4.5.10

CWE Classification

CWE-918

AI Assessment

AI Score 8.7 / 10

AI Severity High

Vendor Mastodon

Product Mastodon

Version 4.5.0-beta.1 to 4.5.9, 4.4.0 to 4.4.16, 4.3.0 to 4.3.22

References

github.com /mastodon/mastodon/security/advisories/GHSA-crr4-7rm4-8gpw

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