CVE-2026-46348

Mastodon: SSRF Bypass via IPv6 Unspecified Address (::)

State
Published
Severity
8.7 High
Published
Jun 24, 2026
Updated
Jun 25, 2026
Reserved
May 13, 2026

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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.

Scores

CVSSScoreVectorSource
4.08.7 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NGitHub_M

Weaknesses

  • CWE-918 Server-Side Request Forgery (SSRF)

Affected Products

ProductVersions
mastodonmastodon
  • >= 4.5.0-beta.1, < 4.5.10Affected

References

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