CVE-2026-33410

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{"affected": [{"affectedData": [{"product": "discourse", "vendor": "discourse", "versions": [{"status": "affected", "version": ">= 2026.1.0-latest, < 2026.1.2"}, {"status": "affected", "version": ">= 2026.2.0-latest, < 2026.2.1"}, {"status": "affected", "version": "= 2026.3.0-latest"}]}], "source": "security-advisories@github.com"}], "configurations": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "matchCriteriaId": "4BE96625-3609-410C-B41E-4A824C1A57C0", "versionEndExcluding": "2026.1.2", "versionStartIncluding": "2026.1.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:discourse:discourse:*:*:*:*:*:*:*:*", "matchCriteriaId": "FD31CF04-CF2F-4FB9-8880-9243BC7671A7", "versionEndExcluding": "2026.2.1", "versionStartIncluding": "2026.2.0", "vulnerable": true}, {"criteria": "cpe:2.3:a:discourse:discourse:2026.3.0:*:*:*:latest:*:*:*", "matchCriteriaId": "E3FE9277-4F6B-4FD0-991F-F0FB8D226E1C", "vulnerable": true}], "negate": false, "operator": "OR"}]}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Discourse is an open-source discussion platform. Versions prior to 2026.3.0-latest.1, 2026.2.1, and 2026.1.2 have two authorization issues in the chat direct message API. First, when creating a direct message channel or adding users to an existing one, the `target_groups` parameter was passed directly to the user resolution query without checking group or member visibility for the acting user. An authenticated chat user could craft an API request with a known private/hidden group name and receive a channel containing that group's members, leaking their identities. Second, `can_chat?` only checked group membership, not the `chat_enabled` user preference. A chat-disabled user could create or query DM channels between other users via the direct messages API, potentially exposing private `last_message` content from the serialized channel response. 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 discusi\u00f3n de c\u00f3digo abierto. Las versiones anteriores a 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 tienen dos problemas de autorizaci\u00f3n en la API de mensajes directos del chat. Primero, al crear un canal de mensajes directos o a\u00f1adir usuarios a uno existente, el par\u00e1metro 'target_groups' se pasaba directamente a la consulta de resoluci\u00f3n de usuarios sin comprobar la visibilidad del grupo o de los miembros para el usuario que actuaba. Un usuario de chat autenticado podr\u00eda elaborar una solicitud de API con un nombre de grupo privado/oculto conocido y recibir un canal que contuviera a los miembros de ese grupo, filtrando sus identidades. Segundo, 'can_chat?' solo comprobaba la pertenencia al grupo, no la preferencia de usuario 'chat_enabled'. Un usuario con el chat deshabilitado podr\u00eda crear o consultar canales de MD entre otros usuarios a trav\u00e9s de la API de mensajes directos, exponiendo potencialmente contenido privado de 'last_message' de la respuesta serializada del canal. Las versiones 2026.3.0-latest.1, 2026.2.1 y 2026.1.2 contienen un parche. No se conocen soluciones alternativas disponibles."}], "id": "CVE-2026-33410", "lastModified": "2026-06-17T10:37:26.793", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.5, "source": "security-advisories@github.com", "type": "Secondary"}, {"cvssData": {"attackComplexity": "LOW", "attackVector": "NETWORK", "availabilityImpact": "NONE", "baseScore": 5.4, "baseSeverity": "MEDIUM", "confidentialityImpact": "LOW", "integrityImpact": "LOW", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N", "version": "3.1"}, "exploitabilityScore": 2.8, "impactScore": 2.5, "source": "nvd@nist.gov", "type": "Primary"}], "ssvcV203": [{"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "ssvcData": {"id": "CVE-2026-33410", "options": [{"exploitation": "none"}, {"automatable": "no"}, {"technicalImpact": "partial"}], "role": "CISA Coordinator", "timestamp": "2026-03-20T16:11:06.356952Z", "version": "2.0.3"}}]}, "published": "2026-03-19T22:16:42.827", "references": [{"source": "security-advisories@github.com", "tags": ["Vendor Advisory"], "url": "https://github.com/discourse/discourse/security/advisories/GHSA-2m5j-6v2r-cq2h"}], "sourceIdentifier": "security-advisories@github.com", "vulnStatus": "Analyzed", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-863"}], "source": "security-advisories@github.com", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2026.1.0-latest,2026.1.2)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[2026.2.0-latest,2026.2.1)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "2026.3.0-latest"}}], "enrichment": {"confidence": 100.0, "confidence_source": "matching", "scores": [{"score": 100.0, "source": "matching"}]}, "original": {"product": "discourse", "source": "cna", "vendor": "discourse"}, "product": "discourse", "vendor": "discourse"}], "analysis": {"en": {"generated_at": "2026-03-24T22:29:03.031486+00:00", "value": {"mitigation_remediation": ["Apply the Discourse patch that includes the updates for versions 2026.3.0\u2011latest.1, 2026.2.1, and 2026.1.2.", "Verify that your installation runs a patched version and test the /direct_messages API for expected authorization enforcement.", "Monitor API usage for anomalous DM creation or queries involving private groups, and review logs for unauthorized access attempts."], "summary": {"action": "Patch", "impact": "Privacy Compromise"}, "threat_synthesis": {"affected_systems": "The affected product is the open\u2011source discussion platform Discourse. Vulnerable versions are all releases prior to 2026.3.0\u2011latest.1, 2026.2.1, and 2026.1.2. Versions 2026.3.0\u2011latest.1, 2026.2.1, and 2026.1.2 contain the fix and are recommended for deployment.", "description_and_impact": "This vulnerability involves two authorization lapses in the chat direct\u2011message API. An authenticated user can supply a hidden or private group name when creating or expanding a DM channel, and the system resolves that name without verifying the creator\u2019s rights to view the group. Consequently the user receives a channel containing all members of the private group, leaking their identities. Additionally, the API\u2019s check for chat ability ignores the individual user\u2019s chat\u2011enabled preference, letting a chat\u2011disabled user create or query DM channels between other participants. The resulting channel response can expose the private last\u2011message content, further compromising confidentiality. The weakness is catalogued as CWE\u2011863: Insufficient Authorization.", "risk_and_exploitability": "The CVSS score of 5.4 reflects a moderate severity, while the EPSS score of less than 1% indicates a low probability of current exploitation. The vulnerability is not listed in the CISA KEV catalog. An attacker needs only authenticated access to the chat API and knowledge of a private group name. The exploit path is straightforward: construct a valid API request to /direct_messages using the target_groups parameter or to query a DM channel, and read the returned data. Once executed, the attacker gains information about private group membership and potentially private last messages, compromising confidentiality but not system control."}}}}, "created": "2026-03-20T08:55:24.987647+00:00", "updated": "2026-03-25T11:54:34.266932+00:00", "vendors": ["discourse", "discourse$PRODUCT$discourse"]}