CVEvulnerability

CVE-2026-47389

8.6 HIGH Published 2026-06-24 Modified 2026-06-25 Official page ↗
Status
Deferred
Published
2026-06-24
Last modified
2026-06-25
Assigner
[email protected]
CVSS 3.1 ([email protected])
8.6 HIGH — CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Weaknesses
CWE-184, CWE-200, CWE-918

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, when using Ruby versions older than 3.4, PrivateAddressCheck.private_address? returns false for IPv4-mapped IPv6 addresses (::ffff:a.b.c.d) corresponding to some private IPv4 addresses, depending on Ruby version, this can include loopback, RFC1918 private networks, and link-local space. An attacker who controls DNS for any domain can publish an AAAA record with such a mapped address; any outbound HTTP fetch Mastodon performs against that hostname then opens a real TCP connection to the underlying IPv4 address, including 127.0.0.1 and cloud-metadata endpoints such as 169.254.169.254. This vulnerability is fixed in 4.5.10, 4.4.17, and 4.3.23.

Related

Weakness · CWE (3)

  • CWE-184 Incomplete List of Disallowed Inputs weakness
  • CWE-200 Exposure of Sensitive Information to an Unauthorized Actor weakness
  • CWE-918 Server-Side Request Forgery weakness

References