AIKIDO-2026-265353

austintoddj/canvas is vulnerable to Server-Side Request Forgery (SSRF)

Server-Side Request Forgery (SSRF)GHSA-5fp8-rp48-gr3c Published Aug 24, 2026

High Risk

This Affects:

austintoddj/canvas

7.0.0 - 7.0.0

Fixed in 7.0.1

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TL;DR

Canvas validates webhook URLs through WebhookUrlValidator, whose ipIsPublic() check delegates to PHP filter_var with FILTER_FLAG_NO_PRIV_RANGE and FILTER_FLAG_NO_RES_RANGE. That check does not extract IPv4 addresses embedded in IPv6 transition literals, so a webhook host given as a 6to4 or NAT64 address that encodes a private, loopback, or link-local IPv4 target is treated as public. A user who can configure a webhook can make the server send requests to internal services, loopback ports, or cloud metadata endpoints. The fix unwraps IPv4-mapped IPv6 addresses and rejects IPv6 transition and special-use ranges before the public-address check.

Who does this affect?

You are affected if you run a version within the vulnerable range and use the outbound webhook integration, where a user-controlled webhook URL is validated before the server sends requests to it.