CVE-2026-26973

{
  "id": "CVE-2026-26973",
  "cveTags": [],
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          "id": "CVE-2026-26973",
          "role": "CISA Coordinator",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "no"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "version": "2.0.3",
          "timestamp": "2026-02-26T20:40:10.083850Z"
        }
      }
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      {
        "type": "Secondary",
        "source": "security-advisories@github.com",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 4.3,
          "attackVector": "NETWORK",
          "baseSeverity": "MEDIUM",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N",
          "integrityImpact": "LOW",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "NONE",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "NONE"
        },
        "impactScore": 1.4,
        "exploitabilityScore": 2.8
      }
    ]
  },
  "affected": [
    {
      "source": "security-advisories@github.com",
      "affectedData": [
        {
          "vendor": "discourse",
          "product": "discourse",
          "versions": [
            {
              "status": "affected",
              "version": "< 2025.12.2"
            },
            {
              "status": "affected",
              "version": ">= 2026.1.0-latest, < 2026.1.1"
            },
            {
              "status": "affected",
              "version": ">= 2026.2.0-latest, < 2026.2.0"
            }
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  "published": "2026-02-26T20:31:37.327",
  "references": [
    {
      "url": "https://github.com/discourse/discourse/security/advisories/GHSA-c587-qx78-vhmx",
      "tags": [
        "Vendor Advisory"
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "type": "Secondary",
      "source": "security-advisories@github.com",
      "description": [
        {
          "lang": "en",
          "value": "CWE-863"
        }
      ]
    },
    {
      "type": "Primary",
      "source": "nvd@nist.gov",
      "description": [
        {
          "lang": "en",
          "value": "CWE-639"
        }
      ]
    }
  ],
  "descriptions": [
    {
      "lang": "en",
      "value": "Discourse is an open source discussion platform. Versions prior to 2025.12.2, 2026.1.1, and 2026.2.0 have an IDOR (Insecure Direct Object Reference) in `ReviewableNotesController`. When `enable_category_group_moderation` is enabled, a user belonging to a  category moderation group can create or delete their own notes on **any** reviewable in the system, including reviewables in categories they do not moderate. The controller used an unscoped `Reviewable.find` and the `ensure_can_see` guard only checked whether the user could access the review queue in general, not whether they could access the specific reviewable. Only instances with `enable_category_group_moderation` enabled are affected. Staff users (admins/moderators) are not impacted as they already have access to all reviewables. The issue is patched in versions 2025.12.2, 2026.1.1, and 2026.2.0 by scoping the reviewable lookup through `Reviewable.viewable_by(current_user)`. As a workaround, disable the `enable_category_group_moderation` site setting. This removes the attack surface as only staff users will have access to the review queue."
    },
    {
      "lang": "es",
      "value": "Discourse es una plataforma de discusión de código abierto. Versiones anteriores a 2025.12.2, 2026.1.1 y 2026.2.0 tienen una IDOR (Referencia Directa Insegura a Objeto) en `ReviewableNotesController`. Cuando `enable_category_group_moderation` está habilitado, un usuario que pertenece a un grupo de moderación de categoría puede crear o eliminar sus propias notas en cualquier elemento revisable del sistema, incluyendo elementos revisables en categorías que no modera. El controlador usó un `Reviewable.find` sin ámbito y la protección `ensure_can_see` solo verificaba si el usuario podía acceder a la cola de revisión en general, no si podía acceder al elemento revisable específico. Solo las instancias con `enable_category_group_moderation` habilitado se ven afectadas. Los usuarios del personal (administradores/moderadores) no se ven afectados ya que ya tienen acceso a todos los elementos revisables. El problema está parcheado en las versiones 2025.12.2, 2026.1.1 y 2026.2.0 al limitar la búsqueda de elementos revisables a través de `Reviewable.viewable_by(current_user)`. Como solución alternativa, deshabilite la configuración del sitio `enable_category_group_moderation`. Esto elimina la superficie de ataque ya que solo los usuarios del personal tendrán acceso a la cola de revisión."
    }
  ],
  "lastModified": "2026-06-17T10:26:28.087",
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