CVE-2026-72916

Mastodon is a free, open-source social network server based on ActivityPub. Prior to 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1, PrivateAddressCheck.private_address? in app/lib/private_address_check.rb normalized IPv4-mapped IPv6 addresses but did not recognize IPv4-compatible IPv6 addresses with IPAddr#ipv4_compat?. An attacker could supply an address in the omitted range to bypass the ALLOWED_PRIVATE_ADDRESSES protection and make Mastodon send HTTP requests to loopback interfaces, potentially accessing private resources and services. Exploitation requires a system that supports the obsolete IPv4-compatible IPv6 mechanism. This issue is fixed in versions 4.4.21, 4.5.14, 4.6.4, and 4.7.0-beta.1.

CVSS

No CVSS.

References

Link	Resource
https://github.com/mastodon/mastodon/commit/18c61f286f1f5718a8f517940ba384866ffa3892
https://github.com/mastodon/mastodon/commit/467c933459c7d0e5513475b9e4888afaedfb1074
https://github.com/mastodon/mastodon/commit/930aa9fee26bf9eaefe27826fa1061288d83373b
https://github.com/mastodon/mastodon/commit/da47a1bd3cd07935d7ca55a1f4f1a76f7f167e0d
https://github.com/mastodon/mastodon/releases/tag/v4.4.21
https://github.com/mastodon/mastodon/releases/tag/v4.5.14
https://github.com/mastodon/mastodon/releases/tag/v4.6.4
https://github.com/mastodon/mastodon/releases/tag/v4.7.0-beta.1
https://github.com/mastodon/mastodon/security/advisories/GHSA-vwhj-3g83-v276

Configurations

No configuration.

History

No history.

Information

Published : 2026-08-10 22:17

Updated : 2026-09-09 20:55

NVD link : CVE-2026-72916

Mitre link : CVE-2026-72916

CVE.ORG link : CVE-2026-72916

JSON object : View

Products Affected

No product.

CWE

CWE-918

Server-Side Request Forgery (SSRF)

CWE-1286

Improper Validation of Syntactic Correctness of Input

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